Emergent temporal signaling in human trabecular meshwork cells: role of TRPV4-TRPM4 interactions

Trabecular meshwork (TM) cells are phagocytic cells that employ mechanotransduction to actively regulate intraocular pressure. Similar to macrophages, they express scavenger receptors and participate in antigen presentation within the immunosuppressive milieu of the anterior eye. Changes in pressure deform and compress the TM, altering their control of aqueous humor outflow but it is not known whether transducer activation shapes temporal signaling. The present study combines electrophysiology, histochemistry and functional imaging with gene silencing and heterologous expression to gain insight into Ca2+ signaling downstream from TRPV4 (Transient Receptor Potential Vanilloid 4), a stretch-activated polymodal cation channel. Human TM cells respond to the TRPV4 agonist GSK1016790A with fluctuations in intracellular Ca2+ concentration ([Ca2+]i) and an increase in [Na+]i. [Ca2+]i oscillations coincided with monovalent cation current that was suppressed by BAPTA, Ruthenium Red and the TRPM4 (Transient Receptor Potential Melastatin 4) channel inhibitor 9-phenanthrol. TM cells expressed TRPM4 mRNA, protein at the expected 130-150 kDa and showed punctate TRPM4 immunoreactivity at the membrane surface. Genetic silencing of TRPM4 antagonized TRPV4-evoked oscillatory signaling whereas TRPV4 and TRPM4 co-expression in HEK-293 cells reconstituted the oscillations. Membrane potential recordings suggested that TRPM4-dependent oscillations require release of Ca2+ from internal stores. 9-phenanthrol did not affect the outflow facility in mouse eyes and eyes from animals lacking TRPM4 had normal intraocular pressure. Collectively, our results show that TRPV4 activity initiates dynamic calcium signaling in TM cells by stimulating TRPM4 channels and intracellular Ca2+ release. It is possible that TRPV4-TRPM4 interactions downstream from the tensile and compressive impact of intraocular pressure contribute to homeostatic regulation and pathological remodeling within the conventional outflow pathway

The effects of dietary lipid sources and lecithin on the production of giant freshwater prawn Macrobrachium rosenbergii larvae in the Mekong Delta region of Vietnam

The giant freshwater prawn, Macrobrachium rosenbergii, is cultured widely in the Mekong Delta region of Vietnam but it is often difficult or expensive for hatchery operators to purchase commercial diets used as a feeding supplement to Artemia nauplii. Therefore, in the present study, the effects of lipid sources and lecithin on the growth and survival rate of M. rosenbergii larvae were examined in order to develop suitable hand-prepared larval diets for seed production of M. rosenbergii in this area. Six egg custard diets consisting of various ratios of lipid (originating from soybean oil and squid oil) and lecithin were used for rearing Macrobrachium rosenbergii larvae. Treatments in which larvae were fed diets containing squid oil exhibited the highest body length and survival rates (7.14-7.43 mm and 51.1-68.1%, respectively), and differed significantly from other treatments (P < 0.05). Use of dietary soybean oil yielded the lowest body length and survival rates (6.29-6.75 mm and 22.0-48.7%, respectively). The supplementation of dietary lecithin did not increase final body weight but did improve larval survival rates. The n-3 HUFA content of prawns fed dietary squid oil was higher than those of animals provided with other diets. These results indicated that the most appropriate diet for rearing M. rosenbergii larvae is the diet containing 3% squid oil and 1.5% lecithin

Baseline characteristics and treatment cost of hepatitis C at Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam in Direct-Acting Antiviral treatment era

Background: Direct-Acting Antivirals (DAAs) are recommended as first-line of drugs for the treatment of chronic hepatitis C virus (HCV) infection in Vietnam in 2016. Since then, Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam introduced DAAs based treatment for all newly presented chronic HCV patients. Here, we report the sociodemographic, clinical, biochemical, and virologic characteristics of patients and the direct medical cost associated with DAAs treatment. Methods: We conducted a retrospective cross-sectional study among chronic HCV patients attended at HTD from March 2016 to October 2017 and treated with DAAs. We used an extract of the patient’s electronic medical record containing demographics, clinical presentations, laboratory results, drug prescription, and cost of treatment at the hospital for data analysis. Results: 2817 chronic HCV patient received DAAs treatment during the study period. The mean age was 55.0 years, and 54.9% (1546/2817) of the patients were female. HCV genotype 1, 2, 3 and 6 prevalence was 32.1% (904/2817), 12.7% (359/2817), 0.4% (10/2817), and 54.7% (1542/2817) respectively. The mean HCV viral load was 3.1 × 106 copies/ml, including 46.9% (1322/2817) had ≥106 copies/ml. 70.64% (1990/2817) and 16.15% (455/28817) of the patients received Sofosbuvir (SOF)/Ledipasvir (LDV) ± Ribavirin (RBV) and SOF/Daclatasvir (DCV) ± RBV therapy respectively. The average drug cost for a 12-week of SOF/LDV ± RBV and SOF/DCV ± RBV treatment was US$2068 - 2230 and US$2417 - 2472, respectively. Conclusion: Genotype 6 was the most predominant genotype in southern Vietnam. The preferred treatment for chronic HCV infection was SOF/LDV ± RBV for 12 weeks.</p

Baseline characteristics and treatment cost of hepatitis C at Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam in Direct-Acting Antiviral treatment era

Background: Direct-Acting Antivirals (DAAs) are recommended as first-line of drugs for the treatment of chronic hepatitis C virus (HCV) infection in Vietnam in 2016. Since then, Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam introduced DAAs based treatment for all newly presented chronic HCV patients. Here, we report the sociodemographic, clinical, biochemical, and virologic characteristics of patients and the direct medical cost associated with DAAs treatment. Methods: We conducted a retrospective cross-sectional study among chronic HCV patients attended at HTD from March 2016 to October 2017 and treated with DAAs. We used an extract of the patient’s electronic medical record containing demographics, clinical presentations, laboratory results, drug prescription, and cost of treatment at the hospital for data analysis. Results: 2817 chronic HCV patient received DAAs treatment during the study period. The mean age was 55.0 years, and 54.9% (1546/2817) of the patients were female. HCV genotype 1, 2, 3 and 6 prevalence was 32.1% (904/2817), 12.7% (359/2817), 0.4% (10/2817), and 54.7% (1542/2817) respectively. The mean HCV viral load was 3.1 × 106 copies/ml, including 46.9% (1322/2817) had ≥106 copies/ml. 70.64% (1990/2817) and 16.15% (455/28817) of the patients received Sofosbuvir (SOF)/Ledipasvir (LDV) ± Ribavirin (RBV) and SOF/Daclatasvir (DCV) ± RBV therapy respectively. The average drug cost for a 12-week of SOF/LDV ± RBV and SOF/DCV ± RBV treatment was US$2068 - 2230 and US$2417 - 2472, respectively. Conclusion: Genotype 6 was the most predominant genotype in southern Vietnam. The preferred treatment for chronic HCV infection was SOF/LDV ± RBV for 12 weeks.</p

Current status of freshwater prawn culture in Vietnam and the development and transfer of seed production technology

In Vietnam, the giant freshwater prawn Macrobrachium rosenbergii is becoming an increasingly important targeted species, as its culture, especially in rice fields, is considered to have the potential to raise income among impoverished farmers. The production of M. rosenbergii based on aquaculture reached over 10 000 tons per year in 2002, having increased from about 2500 tons since the 1990s. Until recently, lack of a stable supply of seed had been an important obstacle to the further expansion and development of M. rosenbergii culture, but cumulative research on larval rearing, especially in the 1990s, has led to the development of new seed production technology based on the 'modified stagnant green water system'. Following its dissemination by the efforts of provincial authorities, hatchery operators, and farmers, the freshwater prawn seed production industry developed rapidly in the Mekong Delta with over 90 hatcheries producing 76.5 million postlarvae in 2003. This is considered to have affected the expansion of rice-prawn farming in the Mekong Delta, leading to increased aquacultural production in the region. This paper reviews the current status of freshwater prawn culture in Vietnam and background history, and presents a socioeconomic evaluation of seed production technology implementation

Evaluation of an algorithm for integrated management of childhood illness in an area of Vietnam with dengue transmission

OBJECTIVES: To determine whether nurses, using the WHO/UNICEF algorithm for integrated management of childhood illness (IMCI), modified to include dengue infection, satisfactorily classified children in an area endemic for dengue haemorrhagic fever (DHF). METHODS: Nurses assessed and classified, using the modified IMCI algorithm, a systematic sample of 1250 children aged 2 months to 10 years (n = 1250) presenting to a paediatric hospital in Dong Nai Province, Vietnam. Their classification was compared with that of a paediatrician, blind to the result of the nurses' assessment, which could be modified in the light of simple investigations, e.g. dengue serology. RESULTS: In children aged 2-59 months (n = 859), the nurses were able to classify, using the modified chart, the presenting illness in &gt;99% of children and found more than one classification in 70%. For the children with pneumonia, diarrhoea, dengue shock syndrome, severe DHF and severe disease requiring urgent admission, the nurse's classification was &gt;60% sensitive and &gt;85% specific compared with that of the paediatrician. For the nurse's classification of DHF the specificity was 50-55% for the children &lt;5 years and in children with definitive dengue serology. Alterations in the DHF algorithm improved specificity at the expense of sensitivity. CONCLUSION: Using the IMCI chart, nurses classified appropriately many of the major clinical problems in sick children &lt;5 years in southern Vietnam. However, further modifications will be required in the fever section, particularly for dengue. The impact of using the IMCI chart in peripheral health stations remains to be evaluated