Pilot randomized sham-controlled trial of self-acupressure to manage the symptom cluster of insomnia, depression, and anxiety in cancer patients undergoing chemotherapy.

PURPOSE: Current evidence for using self-acupressure to manage the cancer-related symptom cluster of insomnia, depression, and anxiety, while promising, is unknown. This study evaluated the feasibility of self-acupressure to manage this symptom cluster and to explore its potential effectiveness. METHODS: Participants were assigned randomly to three study groups, namely the true acupressure (TAP), the sham acupressure (SAP), and the enhanced standard care group (ESC). Participants in the TAP and SAP groups received a training session on acupressure and were required to practice self-acupressure at home once per day for 28 days. The duration of participant involvement was 8 weeks. Patients completed a Numerical Rating Scale (NRS) for each symptom, the Insomnia Severity Index, the Hospital Anxiety and Depression Scale, and the Functional Assessment of Cancer Therapy-General at baseline (T1), post-intervention (T2, week 4), and post follow-up (T3, week 8). RESULTS: The results indicated that the intervention had clinical significance in improving the targeted symptoms and quality of life. In the TAP group, the symptom cluster severity was significantly lower than in the other groups at T2 (p < 0.05). The insomnia severity and anxiety scores in the TAP and SAP groups were significantly lower than those in ESC at T2 and T3 (p < 0.05). CONCLUSION: The trial was feasible. The promising results of the study suggest that further testing of self-acupressure is warranted to inform its effectiveness on the targeted symptom cluster in patients with cancer. A placebo effect was evident alongside therapeutic effects. TRIAL REGISTRATION: ClinicalTrials.gov (ID: NCT03823456) on January 30th, 2019.

Vγ9γδ T Cell Induction by Human Umbilical Cord Blood Monocytes-Derived, Interferon-α-Stimulated Dendritic Cells.

Dendritic cells (DC) are professional antigen-presenting cells that activate T cells to kill cancer cells. The extracellular products of DCs have also been reported to perform the same function. In this study, we examined the in vitro differentiation of umbilical cord blood monocytes into DCs in the presence of GM-CSF, and interferon (IFN)-α. The resulting DC population (called IFN-DCs) were then matured in the presence of TNF-α, and pulsed with total protein extracted from A549 cancer cell line. The pulsed DCs and their conditioned medium were then used to stimulate allogeneic lymphocytes (alloLym). The proliferation and cytotoxicity of alloLym were then determined. The results showed that after 5 days of differentiation, the stimulated monocytes had the typical morphology and characteristic surface markers of DCs. Both unpulsed and pulsed IFN-DCs can induce the proliferation of alloLym, especially Vγ9γδ T cells. The conditioned medium from pulsed and unpulsed IFN-DCs culture also prompted the growth of Vγ9γδ T cells. Moreover, alloLym stimulated with pulsed DCs and their conditioned medium had a greater cytotoxic effect on A549 cells than the ones that were not stimulated. Our results indicated that IFN-DCs and their conditioned medium could induce the anti-tumor immunity in vitro, providing evidence for application of cord blood monocytes-derived, interferon-α- stimulated dendritic cells and their extracellular products in anti-cancer therapy.

Assessment of Cognitive-Driven Performance-Based Activities of Daily Living Dysfunction in Parkinson's Disease.

OBJECTIVES: Parkinson's disease (PD) patients with mild cognitive impairment (PD-MCI) have an increased risk of developing dementia (PDD). As activities of daily living (ADL) impairment is mandatory for the diagnosis of PDD, assessing early signs of instrumental ADL (iADL) dysfunction, especially in PD-MCI, is essential. In PD, self- and caregiver-reported iADL performance is often confounded by motor dysfunction and mood. Objective and time-efficient performance-based measurements are needed to screen for cognitive-related iADL dysfunction. We evaluated the Erlangen Test of Activities of Daily Living in Mild Dementia and Mild Cognitive Impairment (ETAM) in PD and determined its value for characterizing a subgroup of PD-MCI patients with mild performance-based iADL impairment. METHODS: Twenty-one cognitively normal PD patients (PD-NC), 24 PD-MCI patients, and 18 healthy controls (HC) were analyzed. Assessments included the ETAM, a comprehensive neuropsychological test battery, iADL, mood, and motor measurements. RESULTS: PD-MCI patients scored significantly lower on the ETAM total score compared to PD-NC patients (p = .002), whereas HC and PD-NC patients did not statistically differ. No HC scored lower than 27 points (diagnostic cutoff for mild iADL impairment); only PD-MCI patients scored below this cutoff (29.2%) suggesting the ETAM is able to characterize a PD-MCI subgroup with early iADL impairment. PD-MCI patients below the cutoff were more impaired in the attention domain (p = .04). CONCLUSIONS: The ETAM is a potentially valuable clinical assessment, able to detect first signs of iADL dysfunction in PD-MCI. Further studies in larger cohorts are needed to evaluate the prognostic ability for predicting PDD.

New-onset insomnia among cancer patients undergoing chemotherapy: prevalence, risk factors, and its correlation with other symptoms.

STUDY OBJECTIVES: Although insomnia is common among cancer patients, its prevalence remains variable, and its risk factors and correlation with other cancer-related symptoms are not fully explored in the literature. This study aims to determine the prevalence and severity of insomnia as well as risk factors and sleep-related symptom clusters in a sample of cancer patients. METHODS: A cross-sectional survey was conducted collecting data from 213 cancer patients undergoing chemotherapy (age = 53.1 ± 11.3 years, 60% female). Insomnia was measured using the Insomnia Severity Index, a sleep log, and Actigraph, while symptoms were assessed using the Memorial Symptom Assessment Scale and the Hospital Anxiety and Depression Scale. Quality of life was measured with the Functional Assessment of Cancer Therapy-General. RESULTS: Of the participants, 42.8% reported insomnia, with 31.9% of those with insomnia reporting severe insomnia. Insomnia occurrence and severity were not correlated with the participants' characteristics, cancer-related or treatment-related factors, only with the participants' anxiety/depression scores. Principal component analysis showed that insomnia, depression, and anxiety formed a symptom cluster (p < 0.001). There was no difference between sleep parameters measured by Actigraphy in insomnia and non-insomnia participants. CONCLUSION: This study demonstrated that the prevalence of insomnia was high and indicated a symptom cluster of insomnia, depression, and anxiety. Therefore, interventions to reduce this symptom cluster may benefit cancer patients who are trying to manage these symptoms.

Doctoral nursing education in east and Southeast Asia: characteristics of the programs and students' experiences of and satisfaction with their studies.

BACKGROUND: The characteristics of nursing doctoral programs and the doctoral students' experience have not been thoroughly investigated. Hence, this study aimed to describe the characteristics of nursing doctoral programs in East and South East Asian (ESEA) countries and regions from the views of doctoral program coordinators, and to explore the students' experiences of and satisfaction with their doctoral nursing program. METHODS: A cross-sectional survey was conducted using two self-designed questionnaires, one focusing on PhD program coordinators and the other on doctoral students. Characteristics of the nursing doctoral programs focused on program characteristics, faculty characteristics, career pathways for graduates, and challenges for nursing doctoral education. Doctoral students' assessment of study experiences included quality of supervision, doctoral training programs, intellectual/cultural climate of institutions, general facilities/support, and the overall study experience and satisfaction. RESULTS: In the PhD coordinators survey, 46 institutions across nine ESEA countries and regions participated. More than half of nursing departments had academic members from other health science disciplines to supervise doctoral nursing students. The majority of graduates were holding academic or research positions in higher education institutions. Faculty shortages, delays in the completion of the program and inadequate financial support were commonly reported challenges for doctoral nursing education. In the students' survey, 193 doctoral students participated. 88.3% of the students were satisfied with the supervision they received from their supervisors; however, 79% reported that their supervisors 'pushed' them to publish research papers. For doctoral training programs, 75.5% were satisfied with their curriculum; but around half reported that the teaching training components (55.9%) and mobility opportunities (54.2%) were not included in their programs. For overall satisfaction with the intellectual and cultural climate, the percentages were 76.1 and 68.1%, respectively. Only 66.7% of the students felt satisfied with the facilities provided by their universities and nursing institutions. CONCLUSION: Doctoral nursing programs in most of the ESEA countries value the importance of both research and coursework. Doctoral nursing students generally hold positive experiences of their study. However, incorporating more teaching training components, providing more opportunities for international mobility, and making more effort to improve research-related facilities may further enhance the student experience. There is also a need to have international guidelines and standards for quality indicators of doctoral programs to maintain quality and find solutions to global challenges in nursing doctoral education.

Nurses' willingness to care for patients infected with HIV or Hepatitis B / C in Vietnam.

OBJECTIVES: This study examined the factors associated with nurses' willingness to care for patients infected with human immunodeficiency virus (HIV) or hepatitis B or C virus (HBV/HCV) in Vietnam. METHODS: A cross-section of 400 Vietnamese nurses from two hospitals were selected using stratified random sampling, to whom a self-administered questionnaire was administered which included demographic items, previous experience with patients infected with HIV or HBV/HCV, and their attitudes toward these patients. Data was analyzed using descriptive statistics and multiple logistic regression. RESULTS: The lifetime prevalence of needlestick or sharps injury whilst caring for a patient infected with HIV or HBV/HCV was 9 and 15.8%, respectively. The majority of participants expressed a willingness to care for patients infected with HIV (55.8%) or HBV/HCV (73.3%). Willingness to care for HIV-infected patients was positively associated with being 40-49 years of age and confidence in protecting themselves against infection. Regarding HBV/HCV infection, willingness to care was positively associated with individual confidence in protecting themselves against infection. CONCLUSIONS: This study revealed that Vietnamese nurses were somewhat willing to care for patients infected with HIV or HBV/HCV, and this was associated with individual confidence in protecting themselves against infection and with negative attitudes towards HIV and HBV/HCV. Establishing a positive safety culture and providing appropriate professional education to help reduce the stigma towards infected patients offers an effective way forwards to improve quality of care in Vietnam, as elsewhere.

Psychiatric co-morbidity in multiple sclerosis: The risk of depression and anxiety before and after MS diagnosis.

BACKGROUND: Studies of depression and anxiety in multiple sclerosis (MS) patients have reported higher rates in MS patients than the general population. OBJECTIVE: To estimate the risk of depression and anxiety and the use of tricyclic antidepressant and selective serotonin reuptake inhibitors (SSRI) prescriptions, in the pre-diagnostic and the post-diagnostic period of MS compared to the background population. METHODS: A cohort of 5084 MS patients was included and matched with a control population of 24,771 persons linked to nationwide registers. Logistic regression analyses were performed estimating odds ratios (OR). RESULTS: In the pre-diagnostic period, the OR for having a diagnosis of depression and anxiety is 1.4 (95% confidence interval (CI) =1.05-1.88), and the OR of redemption prescriptions of TCAs is 1.90 (CI=1.54-2.34) and OR is 1.34 (CI= 1.20-1.51) for SSRI. In the post-diagnostic period the OR is 1.23 (CI= 0.92-1.64) for depression and anxiety diagnosis. The OR is 6.70 (CI=5.81-7.72) for TCA and OR is 2.46 (CI= 2.25-2.69) for SSRI. CONCLUSION: During both the pre- diagnostic and post-diagnostic period, MS patient have increased risk of depression and anxiety diagnoses and redemption of antidepressant and anxiolytic prescriptions, compared to the background population.

Characterization of rubella virus genotypes among pregnant women in northern Vietnam, 2011-2013.

Rubella virus (RV) infection is an unresolved clinical complication that affects children in developing countries including Vietnam. RV infection during the first trimester of pregnancy causes severe birth defects known as congenital rubella syndrome. This study reports on the genomic characterization of RV strains circulating in northern Vietnam during 2011-2013. RV-IgM positive amniotic fluid specimens were collected from 38 women from northern Vietnam who presented with clinical rubella at the National Hospital of Obstetrics and Gynecology in Hanoi, Vietnam. The RV genes were determined by nested PCR with primers amplifying the 739-nucleotide coding region of the E1 gene. The sequences from the amplified DNA fragments were phylogenetically analyzed and compared to reference RV strains. Seventeen out of 38 samples are positive for RV detecting. All new RV isolates are clustered to genotype 2B. Eighteen amino acid mutations were found in the T and B cell epitopes. These results suggest that genotype 2B RV strains frequently circulate in northern Vietnam. These data describe the RV genotype in Vietnam with the aim of improving maternal and child health in this country.

The patient-breast cancer care pathway: how could it be optimized?

BACKGROUND: A care pathway is defined as patient-focused global care that addresses temporal (effective and coordinated management throughout the illness) and spatial issues (treatment is provided near the health territory in or around the patient's home). Heterogeneity of the care pathways in breast cancer (BC) is presumed but not well evaluated. The OPTISOINS01 study aims to assess every aspect of the care pathway for early BC patients using a temporal and spatial scope. METHODS/DESIGN: An observational, prospective, multicenter study in a regional health territory (Ile-de-France, France) in different types of structures: university or local hospitals and comprehensive cancer centers. We will include and follow during 1 year 1,000 patients. The study consists of 3 work-packages: - Cost of pathway The aim of this WP is to calculate the overall costs of the early BC pathway at 1 year from different perspectives (society, health insurance and patient) using a cost-of-illness analysis. Using a bottom-up method, we will assess direct costs, including medical direct costs and nonmedical direct costs (transportation, home modifications, home care services, and social services), and indirect costs (loss of production). - Patient satisfaction and work reintegration Three questionnaires will assess the patients' satisfaction and possible return to work: the occupational questionnaire for employed women; the questionnaire on the need for supportive care, SCNS-SF34 ('breast cancer' module, SCNS-BR8); and the OUTPASSAT-35 questionnaire. - Quality, coordination and access to innovation Quality will be evaluated based on visits and treatment within a set period, whether the setting offers a multidisciplinary consultative framework, the management by nurse coordinators, the use of a personalized care plan, the provision of information via documents about treatments and the provision of supportive care. The coordination between structures and caregivers will be evaluated at several levels. Day surgery, home hospitalization and one-stop breast clinic visits will be recorded to assess the patient's access to innovation. DISCUSSION: The assessment of care pathways encourages the implementation of new payment models. Our approach could help health care professionals and policymakers to establish other cost-of-illness studies and plan the allocation of resources on a patient basis rather than a visit basis.

Decision support for chronic pain care: how do primary care physicians decide when to prescribe opioids? a qualitative study.

BACKGROUND: Primary care physicians struggle to treat chronic noncancer pain while limiting opioid misuse, abuse, and diversion. The objective of this study was to understand how primary care physicians perceive their decisions to prescribe opioids in the context of chronic noncancer pain management. This question is important because interventions, such as decision support tools, must be designed based on a detailed understanding of how clinicians use information to make care decisions. METHODS: We conducted in-depth qualitative interviews with family medicine and general internal medicine physicians until reaching saturation in emergent themes. We used a funneling approach to ask a series of questions about physicians' general decision making challenges and use of information when considering chronic opioids. We then used an iterative, open-coding approach to identify and characterize themes in the data. RESULTS: We interviewed fifteen physicians with diverse clinical experiences, demographics, and practice affiliations. Physicians said that general decision making challenges in providing pain management included weighing risks and benefits of opioid therapies and time and resource constraints. Also, some physicians described their active avoidance of chronic pain treatment due to concerns about opioid risks. In their decision making, physicians described the importance of objective and consistent information, the importance of identifying "red flags" related to risks of opioids, the importance of information about physical function as an outcome, and the importance of information that engenders trust in patients. CONCLUSIONS: This study identified and described primary care physicians' struggles to deliver high quality care as they seek and make decisions based on an array of incomplete, conflicting, and often untrusted patient information. Decision support systems, education, and other interventions that address these challenges may alleviate primary care physicians' struggles and improve outcomes for patients with chronic pain and other challenging conditions.

Identifying symptom cluster in cancer patients undergoing chemotherapy-in Vietnam: A cross-sectional study.

BACKGROUND: Major cancer treatments can cause a wide range of unpleasant symptoms that burden oncology patients. Different symptom clusters (SC) among cancer patients have been reported in the literature. This study determined the prevalence of symptoms patients experience during chemotherapy treatment and identified symptom clusters among them. METHODS: A cross-sectional study was conducted among 213 cancer patients undergoing chemotherapy in three large hospitals in Vietnam. Symptoms were measured by the Memorial Symptom Assessment Scale. RESULTS: The most prevalent symptoms were lack of appetite (65.3%), difficulty sleeping (62.9%), dry mouth (57.7%), numbness (60.1%), hair loss (43.2%), change in the way food tastes (40.8%), and lack of energy (44.1%). Four symptom clusters were identified. Difficult concentration, pain, cough, and dizziness contributed to the first SC. The second one included lack of energy, numbness, change the food taste, and lack of appetite. Dry mouth, nausea, feeling bloated, problems with urination, hair loss, and constipation made up for the third SC. The final SC consisted of psychological symptoms, which were feeling nervous, feeling drowsy, feeling sad, worrying, problems with sexual interest or activity and difficulty sleeping. CONCLUSION: The study demonstrated that respondents experienced various symptoms and symptom clusters during chemotherapy. These findings can be used to develop clinical guidelines for symptom assessment and management in oncology patients for healthcare professionals.

Drivers of forest cover dynamics in smallholder farming systems: the case of northwestern Vietnam.

The national-scale forest recovery of Vietnam started in the early 1990s and is associated with a shift from net deforestation to net reforestation. Large disparities in forest cover dynamics are, however, observed at the local scale. This study aims to unravel the mechanisms driving forest cover change for a mountainous region located in northwest Vietnam. Statistical analyses were used to explore the association between forest cover change and household characteristics. In Sa Pa district, deforestation rates are decreasing, but forest degradation continues at similar rates. Deforestation is not necessarily associated with impoverished ethnic communities or high levels of subsistence farming, and the largest forest cover dynamics are found in villages with the best socio-economic conditions. Our empirical study does not provide strong evidence of a dominant role of agriculture in forest cover dynamics. It shows that empirical studies on local-scale forest dynamics remain important to unravel the complexity of human-environment interactions.

Characterisation of Soil Bacterial Communities That Exhibit Chemotaxis to Root Exudates from Phosphorus-Limited Plants.

The ability to sense and direct movement along chemical gradients is known as 'chemotaxis' and is a common trait among rhizosphere microorganisms, which are attracted to organic compounds released from plant roots. In response to stress, the compounds released from roots can change and may recruit symbionts that enhance host stress tolerance. Decoding this language of attraction could support the development of microbiome management strategies that would enhance agricultural production and sustainability. In this study, we employ a culture-independent bait-trap chemotaxis assay to capture microbial communities attracted to root exudates from phosphorus (P)-sufficient and P-deficient Arabidopsis thaliana Col-0 plants. The captured populations were then enumerated and characterised using flow cytometry and phylogenetic marker gene sequencing, respectively. Exudates attracted significantly more cells than the control but did not differ between P treatments. Relative to exudates from P-sufficient plants, those collected from P-deficient plants attracted a significantly less diverse bacterial community that was dominated by members of the Paenibacillus, which is a genus known to include powerful phosphate solubilisers and plant growth promoters. These results suggest that in response to P deficiency, Arabidopsis exudates attract organisms that could help to alleviate nutrient stress.

Effects of music intervention combined with progressive muscle relaxation on anxiety, depression, stress and quality of life among women with cancer receiving chemotherapy: A pilot randomized controlled trial.

Beneficial effects of music intervention and progressive muscle relaxation alone on psychological issues were reported, however, studies evaluating their combined effects are limited. This study aimed to investigate the feasibility, acceptability and preliminary effects of music intervention combined with progressive muscle relaxation on anxiety, depression, stress, and quality of life among breast and gynaecological cancer patients receiving chemotherapy. METHODS: The study was carried out from March to May 2022 in an oncology hospital in Vietnam. A single-blinded randomized controlled trial was conducted among 24 women with breast and gynaecological cancer undergoing chemotherapy. The intervention group (n = 12) received a face-to-face training program about music listening and progressive muscle relaxation skills. They then performed the self-practice daily at home for three weeks. The control group (n = 12) received standard care, including health assessment, regular health advice and nutrition consultation. Ten participants in the intervention group were interviewed with open-ended questions to explore the acceptability of the intervention. Anxiety, depression and stress were measured using the Depression Anxiety Stress Scale, while The Functional Assessment of Cancer Therapy-General was used to evaluate the quality of life. The outcome measurements were collected at baseline (T0), post-intervention (3rd week, T1) and follow-up (6th week, T2). Appropriate descriptive statistics were used to depict the outcome measures across study time points. RESULTS: A total of 24 patients were eligible to join, and 20 of them completed the study. Greater reductions in anxiety, depression and stress were observed in the intervention group than in the control group at T1 and T2. Greater improvements on quality of life were found in the intervention group than control group at T1 and T2 with respect to T0. The content analysis supported the acceptable intervention of participants through two themes, perceived beneficial effects on psychological and physical health and willingness to keep practising in the future. CONCLUSIONS: Implementing music intervention combined with progressive muscle relaxation is feasible and had a trend in reducing anxiety, depression and stress levels. A larger scale randomized controlled trial is needed to confirm the effect of the intervention on outcomes. TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov with ID: NCT05262621.

Ethnic minority women's empowerment in agriculture in the central region of Viet Nam.

Gender inequality and women's empowerment are two closely related issues. While the gender inequality index has been assessed by different studies, that of women's empowerment remained limited. In the present work, we attempted to evaluate the women's empowerment index by comparing it with the male partner's empowerment index in the same household. We used the Women's Empowerment in Agriculture Index (WEAI) as a framework for reference. A questionnaire was designed to interview 300 people including both men and women in the same ethnic minority household in central Vietnam. The difference in the empowerment level between men and women was assessed through five-component empowerment indicators: agricultural participation, resource ownership, financial control, social organizations participation, and time usage. The results showed that up to 70% of women were disempowered compared to only 15% of men. The binary logistic model revealed the age at first marriage, the level of children's education, education level, distance to the nearest urban area, and the number of children were associated with women's empowerment; whereas age, income, and the level of gender awareness did not show any correlation.

Elucidating the mechanism of photocatalytic reduction of bicarbonate (aqueous CO2) into formate and other organics.

The photocatalytic reduction of CO2 under solar irradiation is an ideal approach to mitigating global warming, and reducing aqueous forms of CO2 that interact strongly with a catalyst (e.g., HCO3-) is a promising strategy to expedite such reductions. This study uses Pt-deposited graphene oxide dots as a model photocatalyst to elucidate the mechanism of HCO3- reduction. The photocatalyst steadily catalyzes the reduction of an HCO3- solution (at pH = 9) containing an electron donor under 1-sun illumination over a period of 60 h to produce H2 and organic compounds (formate, methanol, and acetate). H2 is derived from solution-contained H2O, which undergoes photocatalytic cleavage to produce •H atoms. Isotopic analysis reveals that all of the organics formed via interactions between HCO3- and •H. This study proposes mechanistic steps, which are governed by the reacting behavior of the •H, to correlate the electron transfer steps and product formation of this photocatalysis. This photocatalysis achieves overall apparent quantum efficiency of 27% in the formation of reaction products under monochromatic irradiation at 420 nm. This study demonstrates the effectiveness of aqueous-phase photocatalysis in converting aqueous CO2 into valuable chemicals and the importance of H2O-derived •H in governing the product selectivity and formation kinetics.

Sleep quality among non-hospitalized COVID-19 survivors: a national cross-sectional study.

Objectives: Insomnia is a common symptom after COVID-19 infection; however, its current evidence was among hospitalized COVID-19 patients. This study aimed to assess the prevalence of insomnia and identify its association with depression and anxiety among non-hospitalized COVID-19 recovered population. Methods: We conducted a cross-sectional online survey of 1,056 COVID-19 survivors within 6 months of initial COVID-19 infection and retrieved did not require hospitalization. The Insomnia Severity Index, and Depression Anxiety and Stress Scale-14 were used. Multivariate logistic regression was used to examine the associations between depressive and anxiety score, and participants' insomnia level. Results: The prevalence of insomnia was 76.1%, and among those, 22.8% of participants scored for severe insomnia. One third of participants reported worse sleep quality, shorter sleep duration, and harder to fall asleep, half reported more awaken nights after COVID-19 infection. Participants with depressive (OR 3.45; 95%CI 1.87-6.34) or anxiety (OR 3.93; 95%CI 2.52-6.13) had significantly higher odds of developing insomnia. Other risk factors of insomnia included pre-existing chronic conditions and higher education level, while COVID-19 symptoms and duration were not significantly associated. Conclusion: Our study highlights the substantial burden of insomnia among non-hospitalized COVID-19 survivors and the significant association of depression and anxiety on the development of this long-term effect of COVID-19. These findings underscore the need for comprehensive interventions that address both sychological and sleeping health in this population.

A novel finding of intra-genus inhibition of quorum sensing in Vibrio bacteria.

Quorum sensing is the process by which microbial cells sense and respond to the co-presence of others in their surrounding, through the detection of their autoinducers associated with gene expression regulation and thereby controlling many physiological processes, such as biofilm formation and/or bioluminescence, etc. In Vibrio bacteria, where quorum sensing is relatively well understood with three commonly known autoinducers (HAI-1, AI-2 and CAI-1), both intra-species and inter-species cell-cell communications occur but no inter-Vibrio-species quorum sensing inhibition has been reported. In this study, by screening bacterial isolated from soil and mud samples in a northern province in Vietnam, we discovered a strain that reduced more than 75% of the bioluminescence of a Vibrio harveyi, with evidence showing that such an inhibition might be associated with quorum sensing inhibition. The strain, designated as XTS1.2.9, was identified to be a Vibrio parahaemolyticus bacterium based on its morphological, physiological, biochemical and phylogenetic characteristics. We also tested XTS1.2.9 for its bioluminescence inhibition against different mutants lacking different quorum sensing autoinducers by using plate assays. The results showed that XTS1.2.9 inhibited the bioluminescence of the mutants having sensor 1, especially the one detecting CAI-1, and lacking sensor for AI-2; while it did not inhibit the mutants having only sensor for AI-2 and lacking sensor 1. Therefore, we propose an intra-genus quorum sensing inhibition mechanism involving CAI-1 to explain for such interactions between Vibrio parahaemolyticus and Vibrio harveyi. This phenomenon is reported for the first time and may have certain scientific and application implications.

Dual cross-linked chitosan/alginate hydrogels prepared by Nb-Tz 'click' reaction for pH responsive drug delivery.

A novel physically and chemically double-crosslinked hydrogel derived from chitosan oligosaccharide/alginate (COS/Alg) was developed by using norbornene (Nb)-tetrazine (Tz) click reaction for ketoprofen delivery. The properties of the hydrogel were evaluated by rheological, FTIR, TGA, XRD, SEM, swelling and drug release studies. The Nb-Tz chemical cross-linking facilitated outstanding hydrophobic drug loading (44% wt/wt of ketoprofen) and sustained release through a hydrophobic interaction mechanism between the drug and the used polysaccharides. The COS/Alg electrostatics network (10/10 of NH2/COOH molar ratio) generated the pH responsiveness, suppressing the release in simulated gastric fluid (below 10% for 2 h) and enhancing the release in simulated intestinal fluids (up to 84% for 24 h). The prepared hydrogel was non-toxic to human HEK-293 cells (95% cell viability). This work opens up a potential approach for preparing hydrophilic hydrogels from natural polysaccharides that can be used in the delivery of hydrophobic drugs.