Acidic pH Levels Research Articles

Enamel resistance, properties of oral fluid and the concentration of 25-нydroxycalciferol in blood serum in children with celiac disease

Aim to study the properties of oral fluid and the concentration of 25-hydroxycalciferol in the blood serum of children with celiac disease due to their great theoretical and practical importance in assessing the resistance of teeth to caries for early diagnosis and choice of adequate preventive measures.
 Material and methods. The study involved 98 children aged 6 to 12 years. In all participants, the following caries-related factors were assessed: oral fluid pH, concentration of Streptococcus mutans in the oral cavity, kinematic viscosity of the oral fluid and salivation rate, remineralizing potential of saliva, intensity of caries, oral hygiene index, concentration of 25-hydroxycalciferol in blood serum.
 Results. A survey of 98 children aged 6 to 12 years showed a high risk for oral diseases in children with a confirmed diagnosis of celiac disease. The main risk factors are: high titer of Streptococcus mutans in the oral fluid, high kinematic viscosity, low salivation rate, acidic pH level of the oral fluid.
 Conclusion. The study showed that children with celiac disease who do not follow a diet have a low concentration of 25-hydroxycalciferol in the blood serum, probably, as the result of the specific vitamin absorption, which, in turn, reduces the remineralizing potential of saliva and the resistance of hard dental tissues to caries.

Features of local etiological factors of periodontal disease in residents of high latitudes

Aim. The purpose of the article is to determine specific regional risk factors for periodontal diseases in residents of the North-East of Russia on a complex clinical and physiological research.Materials and methods. A clinical study of the biophysical properties and composition of oral fluid (salivation rate, pH, viscosity, microcrystallization type, lysozyme activity) in the adult population with inflammatory periodontal diseases were done at dental clinic of the Medical Institute of M.K.Ammosov North-Eastern Federal University, dental clinic "Valeon" and clinical and diagnostic laboratory "Scientific and Practical Center of Phthisiatry" (Yakutsk). A total of 1012 individuals aged 15-19 years old (n = 248) and 35-44 years old (n = 764) were examined. Oral hygiene in the age groups was assessed by the Oral Hygiene Index according to J.C. Green and J.R. Vermillion (1964). In addition, social and hygienic status was assessed according Yu. V.Chizhov's method (2005). Statistical processing was carried out using the SPSS software package, version 22. The research was performed in accordance with the principles and rules of evidence-based medicine.Results. The obtained results determine quantitative and qualitative changes in oral fluid properties. The presence of biological risk factors associated with changes in the composition and properties of the oral fluid, as well as a low sanitary level, which are associated with viscosity increase, salivation rate decrease, a predominance of II and III types of microcrystallization, acidic pH level, a decrease in the level of lysozyme activity, were revealed. The identified risk factors have an impact on the prevalence of periodontal disease in the people of the North and mostly determine their clinical course.Conclusion. The revealed biophysical features of oral fluid in the examined adolescents and adult population of the North-East of Russia are specific regional local risk factors for the development of periodontitis, which must be taken into account when improving the therapeutic and preventive measures of pathological processes of periodontal tissues.

Molecular dynamics study of a covalent organic framework as highly-efficient and biocompatible carriers for doxorubicin delivery: the role of nanopores

The development of highly-efficient loading, targeted delivery and controlled-release of drug carrier systems is of great significance in tumor treatment. Although various kinds of nano-carriers have been widely studied as potential anticancer delivery materials, the major concern of cytotoxicity is still an important issue before real medical applications. This is due to the strong interactions between nano-structure carriers and biomacromolecules. Herein, a covalent organic framework (COF), triazine triphenyl imine (TTI), is proposed as a promising candidate for efficient delivery and release of the anti-cancer drug, doxorubicin (DOX), by using molecular dynamics simulations. Our results demonstrated that despite there being huge pores in TTI, enough contact sites can be provided to attract the drug by π–π interactions between the anthracene rings of DOX and the framework of TTI. The loading capacity of DOX on the TTI monolayer even reach 743% because the nanopores exclude some invalid adsorption sites that exist in other 2D nano-carriers. Interestingly, the DOX molecules can not only spontaneously adsorb on the surface of the TTI monolayer in natural conditions, but also effectively release from the TTI carrier under acidic pH level. For the TTI multilayers, similar loading capacity had also been achieved due to the pore walls also playing a key role in adsorbing the DOX molecules. Moreover, by simulating a model protein interacting with TTI, mild biocompatibility of TTI monolayer and multilayer could also be achieved due to the periodic nanopores limiting the excessive adsorption with the protein that could maintain the native structure. Our results highlight the essential roles of the patterned nano-porous structure in the TTI sheets for both efficient DOX loading and release, with high biocompatibility, and provides valuable insight into COF-based nano-carriers in potential drug delivery applications.

Alterations in Arbuscular Mycorrhizal Community Along a Chronosequence of Teak (Tectona grandis) Plantations in Tropical Forests of China.

Arbuscular mycorrhizal (AM) fungi play a crucial role in promoting plant growth, enhancing plant stress resistance, and sustaining a healthy ecosystem. However, little is known about the mycorrhizal status of teak plantations. Here, we evaluated how the AM fungal communities of rhizosphere soils and roots respond to different stand ages of teak: 22, 35, 45, and 55-year-old from the adjacent native grassland (CK). A high-throughput sequencing method was used to compare the differences in soil and root AM fungal community structures. In combination with soil parameters, mechanisms driving the AM fungal community were revealed by redundancy analysis and the Mantel test. Additionally, spore density and colonization rates were analyzed. With increasing stand age, the AM fungal colonization rates and spore density increased linearly. Catalase activity and ammonium nitrogen content also increased, and soil organic carbon, total phosphorous, acid phosphatase activity, available potassium, and available phosphorus first increased and then decreased. Stand age significantly changed the structure of the AM fungal community but had no significant impact on the diversity of the AM fungal community. However, the diversity of the AM fungal community in soils was statistically higher than that in the roots. In total, nine and seven AM fungal genera were detected in the soil and root samples, respectively. The majority of sequences in soils and roots belonged to Glomus. Age-induced changes in soil properties could largely explain the alterations in the structure of the AM fungal community along a chronosequence, which included total potassium, carbon-nitrogen ratio, ammonium nitrogen, catalase, and acid phosphatase levels in soils and catalase, acid phosphatase, pH, and total potassium levels in roots. Soil nutrient availability and enzyme activity were the main driving factors regulating the shift in the AM fungal community structure along a chronosequence of the teak plantations.

Sugar Industry Waste for Bioelectricity Generation

Microbial fuel cells are presented as the promise of technology to generate electricity by using organic waste. In this research, molasses waste from Laredo Agroindustrial Company was used as fuel, as well as graphite and zinc electrodes, managing to build low-cost cells. It was possible to generate voltage and current peaks of 0.389 ± 0.021 V and 1.179 ± 0.079 mA, respectively. The cells showed that acid pH levels and conductivity values were around 100 mS/cm during the period of the highest bioelectricity generation. The maximum power density was 3.76 ± 0.62 W/cm2 for a current density of 247.55 mA/cm2, showing a peak voltage of 0.459 ± 0.52 V. The yeasts showed a logarithmic phase up to day 25 reflecting an increase in cell growth. Microbial fuel cells are projected to be the most viable solution for organic waste and clean energy generation problems.

Disentangling the Possible Drivers of Indri indri Microbiome: A Threatened Lemur Species of Madagascar.

Research on the gut microbiome may help with increasing our understanding of primate health with species’ ecology, evolution, and behavior. In particular, microbiome-related information has the potential to clarify ecology issues, providing knowledge in support of wild primates conservation and their associated habitats. Indri (Indri indri) is the largest extant living lemur of Madagascar. This species is classified as “critically endangered” by the IUCN Red List of Threatened Species, representing one of the world’s 25 most endangered primates. Indris diet is mainly folivorous, but these primates frequently and voluntarily engage in geophagy. Indris have never been successfully bred under human care, suggesting that some behavioral and/or ecological factors are still not considered from the ex situ conservation protocols. Here, we explored gut microbiome composition of 18 indris belonging to 5 different family groups. The most represented phyla were Proteobacteria 40.1 ± 9.5%, Bacteroidetes 28.7 ± 2.8%, Synergistetes 16.7 ± 4.5%, and Firmicutes 11.1 ± 1.9%. Further, our results revealed that bacterial alpha and beta diversity were influenced by indri family group and sex. In addition, we investigated the chemical composition of geophagic soil to explore the possible ecological value of soil as a nutrient supply. The quite acidic pH and high levels of secondary oxide-hydroxides of the soils could play a role in the folivorous diet’s gut detoxification activity. In addition, the high contents of iron and manganese found the soils could act as micronutrients in the indris’ diet. Nevertheless, the concentration of a few elements (i.e., calcium, sulfur, boron, nickel, sodium, and chromium) was higher in non-geophagic than in geophagic soils. In conclusion, the data presented herein provide a baseline for outlining some possible drivers responsible for the gut microbiome diversity in indris, thus laying the foundations for developing further strategies involved in indris’ conservation.

Leachability of microplastic from different plastic materials

The use of plastic has become common. Large amounts of plastic waste are disposed in landfill without the ability to biodegrade. These plastic materials often disintegrate into microplastic that end up in the leachate, a wastewater stream containing harmful contaminants extracted from the plastic. These particles can eventually contaminate the groundwater. The main objective of this research is to evaluate the leaching of microplastics originated from different types of plastic materials and to evaluate the role of pH in the disintegration process. In this study, seven different types of plastic wastes were investigated. These include Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low-Density Polyethylene (LDPE), Polypropylene (PP), Polystyrene (PS), and Polycarbonate (PC). Batch leaching tests were carried out to generate leachate from these plastic materials. The leachate generated from the test was eventually tested for different water quality parameters. Characterization of microplastic particles was conducted using SEM-EDX, FT-IR and particle size analyser. Results revealed that leachates from PET, LDPE, PS and PP contained fibres in addition to other particles. Results showed that PC (19868 items/L) has the largest, while PET (4099 items/L) has the smallest number of microplastic particles per litre. The results indicated PC (184.1 mg/L) has the highest concentration in mass/L and PS (43.1 mg/L) has the smallest concentrations. The study also revealed pH has a significant impact on the leachability of plastic materials and the turbidity of the leachate. Acidic and basic pH levels are more aggressive to plastic materials than neutral pH levels. SEM analysis found that PET and LDPE leachates contained fibres. EDX analysis conducted on the microplastics indicated the presence of elements indicative of the plastic types. FT-IR analysis was not conclusive for all the materials. Microplastic sizes were mostly small and less than 500 nm for most of the samples. The study concludes that the microplastic particles can disintegrate from the original plastic materials under suitable conditions. The outcome of this study can be used for efficient use of different plastic materials and management of its eventual waste materials.

Extent of bioleaching and bioavailability reduction of potentially toxic heavy metals from sewage sludge through pH-controlled fermentation

Utilization of anaerobically stabilized sewage sludge on arable lands serve as a renewable alternative to chemical fertilizers as it enables recycling of valuable nutrients to food chain. However, probable presence of heavy metals in sewage sludge restricts the use of stabilized sludge on lands. In this study, a novel approach based on pH-controlled fermentation and anaerobic metal bioleaching was developed to reduce ecotoxicity potential of fermented sludge prior to its land application. Sewage sludge was subjected to pH-controlled fermentation process at acidic, neutral, and alkaline pH levels with the aim of increasing metal solubilization and decreasing bioavailable metal fractions through anaerobic bioleaching. Alkaline reactor performed the best among all reactors and resulted in 3-fold higher hydrolysis (34%) and 6-fold higher acidification (19%) efficiencies along with 43-fold (in average) higher metal solubilization than that of neutral pH reactor. As a result of alkaline fermentation, 32–57% of the metals remained as bioavailable and 34–59% of the metals were encapsulated as non-bioavailable within solid fraction of fermented sludge (biosolid), whereas 8–12% of total metal was solubilized into fermentation liquor. Our results reveal that anaerobic bioleaching through alkaline fermentation enables biosolid production with less metal content and low bioavailability, facilitating its utilization for agricultural purposes.

Cadmium-induced toxicity to amphibian tadpoles might be exacerbated by alkaline not acidic pH level

Heavy metal pollution in natural water bodies generally interacting with other environmental stressors produces toxic effects on aquatic organisms. However, toxicological studies exploring interactive effects of these stressors are still limited. Here, tadpoles of the Zhenhai brown frog (Rana zhenhaiensis) were exposed to a 3 × 3 factorial combination, with three cadmium (Cd) concentrations (0, 10 and 100 μg/L) and three pH levels (5.0, 7.23 and 9.0) throughout the developmental period to assess combined toxic effects of Cd × pH on tadpole growth, development and physiology. Nearly all measured traits [including survival, metamorphosis and abnormality rate, metamorphosis time, post-metamorphic size, hepatic metal content, locomotor performance, antioxidant enzyme activity, and erythrocytic nuclear abnormality (ENA) frequency] were affected by Cd exposure, indicating notable Cd-induced toxicity to R. zhenhaiensis tadpoles. The pH level and its interaction with Cd also had significant impacts on most measured traits, such as survival rate, metamorphosis time, froglet jumping distance, hepatic Cd content, ENA frequency. Acidic (or alkaline) environment itself was toxic to tadpoles. However, high pH (but not low pH) level appeared to exacerbate Cd-induced toxicity to tadpoles. Excess free hydrogen ions under acidic environments might inhibit Cd2+ ions binding to cell surface, which reduced Cd accumulation in tissues. Under alkaline environments, other forms of Cd complexes in the aqueous phase probably contributed to promoting Cd accumulation. Our results indicated that Cd exposure could interact with different pH levels, producing diverse combined toxicities to amphibian larvae.

Malabar sole (Cynoglossus macrostomus) skin as promising source of type I acid and pepsin solubilized collagens with potential bioactivity.

The online version contains supplementary material available at (10.1007/s13197-021-04996-8).

Iron(III)-tCDTA derivatives as MRI contrast agents: Increased T1 relaxivities at higher magnetic field strength and pH sensing.

Low molecular weight iron(III) complex-based contrast agents (IBCA) including iron(III) trans-cyclohexane diamine tetraacetic acid [Fe(tCDTA)]- could serve as alternatives to gadolinium-based contrast agents in MRI. In search for IBCA with enhanced properties, we synthesized derivatives of [Fe(tCDTA)]- and compared their contrast effects. Trans-cyclohexane diamine tetraacetic acid (tCDTA) was chemically modified in 2 steps: first the monoanhydride of Trans-cyclohexane diamine tetraacetic acid was generated, and then it was coupled to amines in the second step. After purification, the chelators were analyzed by high-performance liquid chromatography, mass spectrometry, and NMR spectrometry. The chelators were complexed with iron(III), and the relaxivities of the complexes were measured at 0.94, 1.5, 3, and 7Tesla. Kinetic stabilities of the complexes were analyzed spectrophotometrically and the redox properties by cyclic voltammetry. Using ethylenediamine (en) and trans-1,4-diaminocyclohexane, we generated monomers and dimers of tCDTA: en-tCDTA, en-tCDTA-dimer, trans-1,4-diaminocyclohexane-tCDTA, and trans-1,4-diaminocyclohexane-tCDTA-dimer. The iron(III) complexes of these derivatives had similarly high stabilities as [Fe(tCDTA)]- . The iron(III) complexes of the trans-1,4-diaminocyclohexane derivatives had higher T1 relaxivities than [Fe(tCDTA)]- that increased with increasing magnetic field strengths and were highest at 6.8 L·mmol-1 ·s-1 per molecule for the dimer. Remarkably, the relaxivity of [Fe(en-tCDTA)]+ had a threefold increase from neutral pH toward pH6. Four iron(III) complexes with similar stability in comparison to [Fe(tCDTA)]- were synthesized. The relaxivities of trans-1,4-diaminocyclohexane-tCDTA and trans-1,4-diaminocyclohexane-tCDTA-dimer complexes were in the same range as gadolinium-based contrast agents at 3 Tesla. The [Fe(en-tCDTA)]+ complex is a pH sensor at weakly acidic pH levels, which are typical for various cancer types.

Heavy metal- and organic-matter pollution due to self-heating coal-waste dumps in the Upper Silesian Coal Basin (Poland)

This study provides potential insight between self-heating coal-waste dumps and related environmental pollution in southern Poland. Samples collected from dumps in the Upper Silesian Coal Basin were used to quantify released contents of organic- and inorganic pollutants, i.e., polycyclic aromatic hydrocarbons (PAHs) and trace elements (Pb, Cd, Cr, Cu, Zn, Ni, Hg, As). Elevated Hg concentrations (~100–1078 mg/kg) and Pb (~600–2000 mg/kg) attest to the evaporation of these metals from deeper parts of the dumps. The acidic pH levels (3.0–4.5) may help to mobilize these elements. Pearson’s correlation coefficients for samples analyzed by AAS and ICP-MS indicate a similar origin for Cd, Zn, and As. Mostly 2- and 3-ring PAHs, especially anthracene in burnt soil, dominate in the samples. Chlorinated PAHs, thiophenol, pyridines, quinolines (and derivatives) in thermally-altered samples, and waste containing pyrolytic bitumen indicate coking conditions. The high levels of Hg, Pb, and Cd, and chlorinated PAHs and nitrogen heterocycles formed or enriched during self-heating in these dumps should be deemed a significant environmental hazard. Calculating the lifetime cancer risks due to PAHs and heavy metals accumulations in the dumps are substantial, and access to these dumps should be prohibited.

Alleviatory effects of Silicon on the morphology, physiology, and antioxidative mechanisms of wheat (Triticum aestivum L.) roots under cadmium stress in acidic nutrient solutions

Silicon (Si), as a quasi-essential element, has a vital role in alleviating the damaging effects of various environmental stresses on plants. Cadmium (Cd) stress is severe abiotic stress, especially in acidic ecological conditions, and Si can demolish the toxicity induced by Cd as well as acidic pH on plants. Based on these hypotheses, we demonstrated 2-repeated experiments to unfold the effects of Si as silica gel on the root morphology and physiology of wheat seedling under Cd as well as acidic stresses. For this purpose, we used nine treatments with three levels of Si nanoparticles (0, 1, and 3 mmol L−1) derived from sodium silicate (Na2SiO3) against three concentrations of Cd (0, 50, and 200 µmol L−1) in the form of cadmium chloride (CdCl2) with three replications were arranged in a complete randomized design. The pH of the nutrient solution was adjusted at 5. The averages of three random replications showed that the mutual impacts of Si and Cd in acidic pH on wheat roots depend on the concentrations of Si and Cd. The collective or particular influence of low or high levels of Si (1 or 3 mM) and acidic pH (5) improved the development of wheat roots, and the collective influence was more significant than that of a single parallel treatment. The combined effects of low or high concentrations of Cd (50 or 200 µM) and acidic pH significantly reduced root growth and biomass while increased antioxidants, and reactive oxygen species (ROS) contents. The incorporation of Si (1 or 3 mmol L−1) in Cd-contaminated acidic nutrient solution promoted the wheat root growth, decreased ROS contents, and further increased the antioxidants in the wheat roots compared with Cd single treatments in acidic pH. The demolishing effects were better with a high level of Si (3 mM) than the low level of Si (1 Mm). In conclusion, we could suggest Si as an effective beneficial nutrient that could participate actively in several morphological and physiological activities of roots in wheat plants grown under Cd and acidic pH stresses.

Adubação potássica na qualidade de frutos de pessegueiro

Para pessegueiros produzidos na região sul do Brasil ainda são escassas as informações sobre a influência da adubação potássica sobre a qualidade dos frutos. Deste modo, o presente trabalho teve como objetivo avaliar os atributos físico-químicos e compostos bioativos dos frutos de pessegueiros submetidos a diferentes doses de potássio aplicadas no solo por três safras consecutivas. O experimento foi realizado estudando a cultivar Sensação em um pomar comercial no município de Morro Redondo, RS – Brasil, durante as safras de 2016, 2017 e 2018. Os pessegueiros da cultivar Sensação foram adubados com potássio (K) nas doses de 0, 40, 80, 120 e 160 kg ha-1 de K2O na forma de cloreto de potássio, aplicadas na superfície do solo. Após a colheita foram determinados os teores de sólidos solúveis (SS), acidez titulável (AT), relação SS/AT, pH, coloração da polpa, firmeza da epiderme e da polpa, teor de carotenoides totais, compostos fenólicos totais e atividade antioxidante. A firmeza da epiderme, a relação SS/AT e a concentração de carotenoides dos pêssegos responderam à adubação potássica, mas apenas em alguns ciclos de produção. Os parâmetros de coloração, firmeza da polpa, sólidos solúveis, pH do suco, fenóis totais e atividade antioxidante dos pêssegos não alteraram em decorrência da aplicação de potássio ao solo.

Tumor microenvironment triple-responsive nanoparticles enable enhanced tumor penetration and synergetic chemo-photodynamic therapy

A novel combined chemo/photodynamic therapy has been developed to use pH/ROS/MMP-2 triple-responsive drug nanocarriers for treating solid tumor with an extraordinarily high efficiency. The designed poly(ethylene glycol)-peptide-poly(ω-pentadecalactone-co-N-methyldiethyleneamine-co-3,3′-thiodipropionate) (PEG-M-PPMT) nanoparticles (NPs) encapsulating anticancer drug sorafenib (SRF) and photosensitizer chlorin e6 (Ce6) are stable in serum-containing aqueous media and can effectively accumulate in tumor as a result of the EPR effect after intravenous administration in vivo. In the presence of MMP-2 overexpressed in extracellular tumor matrix, the PEG-M-PPMT NPs can partially shed PEG corona to form smaller particles and penetrate deep into tumor tissue. After uptake by tumor cells, the acidic endosomal pH and high intracellular ROS level would trigger substantial swelling of the NPs to accelerate the drug release for rapid killing of the cancer cells. In the current combined chemo/photodynamic therapy, the intracellular ROS generation in tumor is amplified by photosensitizer Ce6 activated with external laser irradiation. As the result, the highly elevated intracellular ROS concentration can both directly induce apoptosis of ROS-stressed tumor cells and magnify acceleration of the drug release from the ROS-responsive PEG-M-PPMT NPs to gain extraordinary therapeutic efficacy. In particular, after the chemo-photodynamic therapeutic treatment with SRF/Ce6-loaded PEG-M-PPMT nanoparticles, all human lung tumors (A549) xenografted in nude mice shrank substantially with approximately 29% of the tumors being completely eradicated. Additionally, SRF/Ce6-loaded PEG-M-PPMT NPs show negligible in vivo toxicity toward major organs such as heart, liver, spleen, lung and kidney. These results demonstrate great potential of the combined chemo/photodynamic therapy based on the stimuli-responsive PEG-M-PPMT nanoparticles for efficient tumor treatment.

Hypoxia-induced GPR4 suppresses trophoblast cell migration and proliferation through the MAPK signaling pathway

Pre-eclampsia (PE), a common pregnancy-systemic syndrome, is characterized by proteinuria and hypertension and is the leading cause of maternal and fetal mortality. Thus, we aim to investigate the role of G-Protein Coupled Receptor 4 (GPR4) in PE and the underlying molecular mechanism. In this study, GSE66273 microarray data were obtained from the Gene Expression Omnibus(GEO) database of the National Center for Biotechnology Information, and Gene set enrichment analysis (GSEA) was performed by GSEA software. qRT-PCR and Immunohistochemistry (IHC) or western blotting were used to assay for the expression of GPR4 in PE placentas and HTR8/SVneo cells. The influence of acidosis and hypoxia environments on the expression of GPR4 was explored using western blotting. Cell proliferation and migration of HTR8/SVneo cells were measured using EdU and MTT assays and migration assay, respectively. Moreover, expressions of MEK1/2, p-MEK1/2, ERK1/2, and p-ERK1/2 in HTR8/SVneo cells were assayed by western blotting. Our data demonstrated that the expression of GPR4 was up regulated in PE placentas. Increase in acidic pH and hypoxic levels increased the expression of GPR4 in HTR8/SVneo cells. GPR4 inhibited cell proliferation and migration in the HTR8/SVneo cells. GPR4 silencing enhanced the phosphorylation of p-MEK1/2and p-ERK1/2 in HTR8/SVneo cells. Additionally, we found that pathway inhibitor partially reversed the effects of GPR4 on proliferation and migration of HTR8/SVneo cells. In conclusions, these results show that GPR4 suppressed cell proliferation and migration by inhibiting MAPK signaling pathway in PE.

Addicted to Acidic Microenvironment.

Acidic pH levels are often observed in growing tumors, with profound effects on cancer cells and surrounding microenvironment. In this issue of Developmental Cell, Funato etal. (2020) show that expression of oncogenic phosphatase of regenerating liver 3 (PRL3) shifts cellular preference for environmental pH, leading to acid addiction.

Evaluation of in vitro and in vivo Efficacy of a Novel Amphotericin B-Loaded Nanostructured Lipid Carrier in the Treatment of Leishmania braziliensis Infection.

BackgroundLeishmaniasis is a neglected disease, and the current therapeutic arsenal for its treatment is seriously limited by high cost and toxicity. Nanostructured lipid carriers (NLCs) represent a promising approach due to high drug loading capacity, controlled drug release profiles and superior stability. Here, we explore the efficacy of a unique pH-sensitive amphotericin B-loaded NLC (AmB-NLC) in Leishmania braziliensis infection in vitro and in vivo.Methods and ResultsAmB-NLC was assessed by dynamic light scattering and atomic force microscopy assays. The carrier showed a spherical shape with a nanometric size of 242.0 ± 18.3 nm. Zeta potential was suggestive of high carrier stability (−42.5 ± 1.5 mV), and the NLC showed ~99% drug encapsulation efficiency (EE%). In biological assays, AmB-NLC presented a similar IC50 as free AmB and conventional AmB deoxycholate (AmB-D) (11.7 ± 1.73; 5.3 ± 0.55 and 13 ± 0.57 ng/mL, respectively), while also presenting higher selectivity index and lower toxicity to host cells, with no observed production of nitric oxide or TNF-α by in vitro assay. Confocal microscopy revealed the rapid uptake of AmB-NLC by infected macrophages after 1h, which, in association with more rapid disruption of AmB-NLC at acidic pH levels, may directly affect intracellular parasites. Leishmanicidal effects were evaluated in vivo in BALB/c mice infected in the ear dermis with L. braziliensis and treated with a pentavalent antimonial (Sb5+), liposomal AmB (AmB-L) or AmB-NLC. After 6 weeks of infection, AmB-NLC treatment resulted in smaller ear lesion size in all treated mice, indicating the efficacy of the novel formulation.ConclusionHere, we preliminarily demonstrate the effectiveness of an innovative and cost-effective AmB-NLC formulation in promoting the killing of intracellular L. braziliensis. This novel carrier system could be a promising alternative for the future treatment of cutaneous leishmaniasis.

Intracellular activation of full-length human TREK-1 channel by hypoxia, high lactate, and low pH denotes polymodal integration by ischemic factors.

TREK-1, a two-pore domain potassium channel, responds to ischemic levels of intracellular lactate and acidic pH to provide neuroprotection. There are two splice variants of hTREK1: the shorter splice variant having a shorter N-terminus compared with the full-length hTREK1 with similar C-terminus sequence that is widely expressed in the brain. The shorter variant was reported to be irresponsive to hypoxia-a condition attributed to ischemia, which has put the neuroprotective role of hTREK-1 channel into question. Since interaction between N- and C-terminus of different ion channels shapes their gating, we re-examined the sensitivity of the full-length as well as the shorter hTREK-1 channel to intracellular hypoxia along with lactate. Single-channel data obtained from the excised inside-out patches of the full-length channel expressed in HEK293 cells indicated an increase in activity as opposed to a decrease in activity in the shorter isoform. However, both the isoforms showed an increase in activity under combined hypoxia, 20mM lactate, and low pH6 condition, albeit with subtle differences in their individual actions, confirming the neuroprotective role played by hTREK-1 irrespective of the differences in the N-terminus among the splice variants. Furthermore, E321A mutant that disrupts the interaction of the C-terminus with the membrane showed a decrease in activity with hypoxia indicating the importance of the C-terminus in the hypoxic response of the full-length hTREK-1. We propose an increase in activity of both the splice variants of hTREK-1 in combined hypoxia, high lactate, and low pH conditions typically associated with ischemia provides neuroprotection.

Pengaruh Nisbah C/N Campuran Limbah Milk Tea dan Molasses Terhadap Jumlah Bakteri Asam Laktat, pH, Perubahan Fisik Warna, dan Aroma pada Probiotik

The objective of the research is to identify the effect of various C/N ratio mixed of milk tea waste and molasses on amount of lactic acid bacteria, pH, physical changes color and aroma in probiotics. The material used in this research are milk tea waste and molasses, fermented in anaerobic. The research method uses a Completely Randomized Design (CRD) by 3 treatments, which are P1 = C/N ratio 25, P2 = C/N ratio 30, P3 = C/N ratio35, with 6 repetitions. The measured parameters are amount of lactic acid bacteria, the pH and physical changes color and aroma. The data were analyzed by Analysis of Variance (ANOVA) method based of Tukey Test. The results of this research showed that there is a significant effect (P < 0,05) between a various of C/N ratio on amount of lactic acid bacteria, pH levels and physical changes color and aroma in the results of fermentation (probiotics). The best respond is on the C/N ratio 30, so it can produced high amount of lactic acid bacteria with an average of 2,06 x 109 CFU/mL, an average pH of 3,75 and physical changes in color and aroma.