Antibacterial effects of 18 medicinal plants used by the Khyang tribe in Bangladesh

Context: The resistance of bacteria to antibiotics is raising serious concern globally. Asian medicinal plants could improve the current treatment strategies for bacterial infections. The antibacterial properties of medicinal plants used by the Khyang tribe in Bangladesh have not been investigated.

Objective: The present study examines the antibacterial properties of 18 medicinal plants used by the Khyang tribe in day-to-day practice against human pathogenic bacteria.

Materials and methods: Leaves, bark, fruits, seeds, roots and rhizomes from collected plants were successively extracted with hexane, ethyl acetate and ethanol. The corresponding 54 extracts were tested against six human pathogenic bacteria by broth microdilution assay. The antibacterial mode of actions of phytoconstituents and their synergistic effect with vancomycin and cefotaxime towards MRSA was determined by time-killing assay and synergistic interaction assay, respectively.

Results and discussion: Hexane extract of bark of Cinnamomum cassia (L.) J. Presl. (Lauraceae) inhibited the growth of MRSA, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii with MIC values below 100 µg/mL. From this plant, cinnamaldehyde evoked at 4?×?MIC in 1?h an irreversible decrease of MRSA count Log10 (CFU/mL) from 6 to 0, and was synergistic with vancomycin for MRSA with fractional inhibitory concentration index of 0.3.

Conclusions: Our study provides evidence that the medicinal plants in Bangladesh have high potential to improve the current treatment strategies for bacterial infection.     

Seasonal variation in the association between household food insecurity and child undernutrition in Bangladesh: Mediating role of child dietary diversity

Household food insecurity (HFI) and child dietary diversity (CDD) are variable across seasons. We examined seasonal variation in HFI and child undernutrition association and tested how CDD mediates this association. We analyzed data for 26,353 children aged 6–59 months drawn from nationally representative cross-sectional Food Security and Nutrition Surveillance Project data collected during 2012–2014 in Bangladesh across three seasons annually: Post-Aman harvest (January–April); Monsoon (May–August); and Post-Aus harvest (September–December). Multivariable logistic regression analysis adjusted for individual, maternal, household and geographical characteristics reveals that children of food-insecure households were more likely than food-secure households to be stunted (adjusted odds ratio, AOR: 1.12; 95% confidence interval, CI: 1.02–1.23; p < 0.05), wasted (AOR: 1.21; 95% CI: 1.05–1.39; p < 0.01) and underweight (AOR: 1.16; 95% CI: 1.04–1.3; p < 0.01). CDD mediated 6.1% of the total effect of HFI on underweight. These findings varied across seasons. HFI was associated with greater odds of underweight during Monsoon (AOR: 1.32; 95% CI: 1.08–1.62; p < 0.01) and Post-Aus (AOR: 1.21; 95% CI: 1.06–1.37; p < 0.01) while wasting during Post-Aus (AOR: 1.65; 95% CI: 1.35–2.01; p < 0.001). CDD largely mediated the total effect of HFI on underweight during the Post-Aman in 2012–2014 (23.2%). CDD largely mediated the total effect of HFI on wasting (39.7%) during Post-Aman season in 2014 and on underweight (13.7%) during the same season in 2012. These findings demonstrate that HFI is seasonally associated with child undernutrition and mediated by CDD as well in Bangladesh and seasonality and diversity should be considered while designing appropriate population-level food-based interventions to resolve child undernutrition.     

Use of designing for behaviour change framework in identifying and addressing barriers to and enablers of animal source feeding to children ages 8–23 months in Bandarban Hill District in Bangladesh: Implications for a nutrition-sensitive agriculture programme

Inadequate diet quality is a cause of undernutrition among children 6–23 months of age in Bangladesh, particularly in remote and isolated areas such as Bandarban District. Feeding animal source foods can help to combat stunting and wasting problems among children, but it may not be accessible or acceptable. A barrier analysis using the Designing for Behavior Change Framework was conducted in Bandarban district with participants from 4 ethnic groups, to explore potential barriers and key motivators by examining 12 behavioural determinants of consumption of animal-source food in complementary feeding for children 8–23 months. Data were collected from 45 mothers of children 8–23 months, who provided animal-source foods to their children (doers), and from 45 mothers who did not (non-doers), for a total of 90 interviews. Nine determinants were statistically significantly different between doers and non-doers as follows: self-efficacy, positive consequences, negative consequences, social norms, access, reminders, perceived risk, perceived severity and perceived action efficacy. Nearby access to purchase animal-source foods, rearing poultry or livestock at home and the support of household and community members are enablers to feeding animal-source food. In contrast, these same factors are barriers for non-doers. The lack of money to spend on animal-source foods is also a barrier. An integrated nutrition-sensitive and gender-transformative animal-based food production, and inclusive market programme could increase access to meat and eggs at the household level, increase opportunities to earn income and support gender-equitable household workloads and decision-making for optimal child feeding.     

Unexpected complication of arteriovenous fistula of the left common carotid to internal jugular vein following central venous catheterization

Incidence of inadvertent arterial puncture secondary to central venous catheter insertion is not common with an arterial puncture rate of<1%.This is due to the advancements and wide availability of ultrasound to guide its insertion.Formation of arteriovenous fistula after arterial puncture is an unexpected complication.Till date,only five cases(including this case)of acquired arteriovenous fistula formation has been described due to inadvertent common carotid puncture.The present case is a 26-year-old man sustained traumatic brain injuries,chest injuries and multiple bony fractures.During resuscitative phase,attempts at left central venous catheter via left internal jugular vein under ultrasound guidance resulted in inadvertent puncture into the left common carotid artery.Surgical neck exploration revealed that the catheter had punctured through the left internal jugular vein into the common carotid artery with formation of arteriovenous fistula.The catheter was removed successfully and common carotid artery was repaired.Postoperatively,the patient recovered and clinic visits revealed no neurological deficits.From our literature review,the safest method for removal is via endovascular and open surgical removal.The pull/push technique(direct removal with compression)is not recommended due to the high risk for stroke,bleeding and hematoma formation.     

Substituted phenyl containing 1,3,4-oxadiazole-2-yl-but-2-enamides: synthesis and preliminary evaluation as promising anticonvulsants

A series of 3-(4-substitutedphenyl)-N-(5-(4-substitutedphenyl-1,3,4-oxadiazol-2-yl)but-2-enamide were synthesized using pharmacophoric elements for in vivo anticonvulsant activity yielding two potent candidates (4d and 4j) in the Phase I and Phase II screening employing maximal electroshock seizure and subcutaneous pentylenetetrazole test having minimal neurotoxicity. Their Phase II screen depicted an increment of nearly 2–10 times for MES and 7–67 folds for scPTZ in the therapeutic index and protective index—the two mainstays in the drug discovery.     

Bradykinin induces NO and PGF2α production via B2 receptor activation from cultured porcine basilar arterial endothelial cells

Our previous in vitro study demonstrated that bradykinin (BK) induced relaxation and contraction of porcine basilar artery (PBA) mediated via activation of endothelial B₂ receptors. The main relaxing and contracting factors appeared to be nitric oxide (NO) and prostaglandin (PG) H₂, respectively, but not thromboxane A₂. After obtaining these findings, we succeeded in cultivating endothelial cells isolated from the PBA. Although PGH₂ has different functionally active isoforms, including PGD₂, PGE₂, and PGF_2α, we have not yet clarified which of them is responsible for BK-induced contraction. Therefore, we attempted to quantify NO and PG production from cultured porcine basilar arterial endothelial cells (PBAECs) and to identify which of the PGs was involved in this contraction. The cultured PBAECs produced NO spontaneously, and BK enhanced this production in a concentration-dependent manner. The NO synthase inhibitor Nω-nitro-l-arginine (L-NNA) and the B₂ receptor antagonist HOE-140, but not the B₁ receptor antagonist des-Arg⁹, [Leu⁸]-BK, completely abolished it. In a functional study, PGD₂, PGE₂, and PGF_2α induced concentration-dependent contractions in isolated porcine basilar arterial rings, the order of maximum contraction being PGF_2α?>?PGE₂?>?PGD₂. The cultured PBAECs produced PGD₂, PGE₂, and PGF_2α spontaneously, and BK significantly enhanced the production of PGF_2α, but not that of PGD₂ and PGE₂. The B₂, but not B₁, antagonist completely abolished the BK-enhanced production of PGF_2α. These results suggest that BK induces production of NO and PGF_2α simultaneously from PBAECs via B₂ receptor activation.     

Keyhole limpet hemocyanin augmented the killing activity,cytokine production and proliferation of NK cells,and inhibited the proliferation of Meth A sarcoma cells in vitro

Objective:

Keyhole limpet hemocyanin (KLH) is a popular tumor vaccine carrier protein and an immunostimulant. The present study aimed to investigate the immunoregulatory activity of KLH on cytotoxicity, cytokines production, and proliferation of natural killer (NK) cells. Moreover, antiproliferative activity of KLH on Meth A sarcoma cells was studied.

Materials and Methods:

Cytotoxicity was determined with killing ability of NK cells against yeast artificial chromosome (YAC)-1 cells. Interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) productions by NK cells were measured by enzyme-linked immunosorbent assay (ELISA). Proliferations of NK and Meth A cells were determined by [³H]thymidine incorporated proliferation and 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) methods, respectively.

Results:

KLH at 6.25, 12.5, and 25 μg/well augmented cytotoxicity of NK cells against YAC-1 cells by 2.5, three, and five-times, respectively. KLH at 25 μg/well enhanced IFN-γ and TNF-α productions by 17- and 23-folds, respectively. The proliferation of NK cells was three times stimulated by KLH. The proliferation of Meth A cells was markedly inhibited by all the doses; the highest (4-folds higher) inhibition was observed at a dose of KLH (25 μg/well).

Conclusion:

The study demonstrated the anticancer activity of KLH acting through the induction of NK cells and inhibition of cancer cells. KLH, therefore, may be a good candidate for an anticancer agent alone or in combination with other chemotherapeutic agents.KEY WORDS: Anticancer activity, cytotoxicity, cytokines, Keyhole limpet hemocyanin, Natural Killer cells, Meth A sarcoma cells, YAC-1 cells     

The Effect of Tropical Environment on Fatigue Failure in Royal Malaysian Airforce (RMAF) Aircraft Structure and Operational Readiness

The environmental condition in which the Royal Malaysian Airforce is currently operating its aircraft is prone to corrosion. This is due to the high relative humidity and temperature. With most of its aircraft being in the legacy aircraft era, the aircraft’s main construction consists of the aluminium 2024 material. However, this material is prone to corrosion, thus reducing fatigue life and leading to fatigue failure. Using the concept of either Safe Life or Damage Tolerance as its fatigue design philosophy, the RMAF adopts the Aircraft Structure Integrity Program (ASIP) to monitor its structural integrity. With the current problem of not having the structural limitation on corrosion-damaged structure, the RMAF has embarked on its fatigue testing method. Finite Element (FE) studies and flight tests were conducted, and the outcome is summarized. The conclusion is that the longeron tested on the aircraft can withstand the operational load, and its yield strength is below the ultimate yield strength of the material. These research outcomes will also enhance the ASIP for other aircraft platforms in the RMAF fleet for its structure life assessment or service life extension program.     

Prevalence of Neutralizing Antibodies to Canine Distemper Virus and Response to Vaccination in Client-Owned Adult Healthy Dogs

Re-vaccinations against canine distemper virus (CDV) are commonly performed in 3-year intervals. The study’s aims were to determine anti-CDV antibodies in healthy adult dogs within 28 days of vaccination against CDV, and to evaluate factors associated with the presence of pre-vaccination antibodies and with the antibody response to vaccination. Ninety-seven dogs, not vaccinated within 1 year before enrollment, were vaccinated with a modified live CDV vaccine. A measurement of the antibodies was performed before vaccination (day 0), on day 7, and 28 after the vaccination by virus neutralization. A response to vaccination was defined as a ≥4-fold titer increase by day 28. Fisher’s exact test was used to determine factors associated with a lack of antibodies and vaccination response. In total, 94.8% of the dogs (92/97; CI 95%: 88.2–98.1) had antibodies (≥10) prior to vaccination. A response to vaccination was not observed in any dog. Five dogs were considered humoral non-responders; these dogs neither had detectable antibodies before, nor developed antibodies after vaccination. Young age (<2 years) was significantly associated with a lack of pre-vaccination antibodies (p = 0.018; OR: 26.825; 95% CI: 1.216–1763.417). In conclusion, necessity of re-vaccination in adult healthy dogs should be debated and regular vaccinations should be replaced by antibody detection.     

Tuning the mechanical properties of silicene nanosheet by auxiliary cracks: a molecular dynamics study

Silicene has become a topic of interest nowadays due to its potential application in various electro-mechanical nanodevices. In our previous work on silicene, fracture stresses of single crystal and polycrystalline silicene have been investigated. Existence of defects in the form of cracks reduces the fracture strength of silicene nanosheets to a great extent. In this study, an engineering way has been proposed for improving the fracture stress of silicene nanosheets with a pre-existing crack by incorporating auxiliary cracks symmetrically in a direction perpendicular to the main crack. We call this mechanism the “Failure shielding mechanism”. An extensive molecular dynamics simulation based analysis has been performed to capture the atomic level auxiliary crack-main crack interactions. It is found that the main crack tip stress distribution is significantly changed with the presence of auxiliary cracks for loading along both armchair and zigzag directions. The effects of temperature and the crack propagation speed of silicene have also been studied. Interestingly, in the case of loading along the zigzag direction, SW defect formation is observed at the tip of main crack. This leads to a reduction of the tip stress resulting in a more prominent failure shielding in case of zigzag loading than in armchair loading. Moreover, the position and length of the cracks as well as the loading directions have significant impacts on the tip stress distribution. Finally, this study opens the possibilities of strain engineering for silicene by proposing an engineering way to tailor the fracture strength of silicene.

Inclusion of auxiliary cracks increases the fracture stress of silicene nanosheets with a pre existing crack.