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Abstract Pseudomonas aeruginosa is an opportunistic pathogen that recently has been increasingly isolated from foods, especially from minimally processed fish-based products. Those are preserved by the addition of sodium chloride (NaCl) and packaging in a modified atmosphere. However, the current trends of minimizing NaCl content may result in an increased occurrence of P. aeruginosa. NaCl can be replaced with potassium chloride (KCl) or sodium salts of organic acids. Herein, we examined the antimicrobial effects of KCl, sodium lactate (NaL), sodium citrate (NaC), and sodium acetate (NaA) against P. aeruginosa NT06 isolated from fish. Transcriptome response of cells grown in medium imitating a fish product supplemented with KCl and KCl/NaL/NaC and maintained under microaerophilic conditions was analysed. Flow cytometry analysis showed that treatment with KCl and KCl/NaL/NaC resulted in changed metabolic activity of cells. In response to KCl and KCl/NaL/NaC treatment, genes related to cell maintenance, stress response, quorum sensing, virulence, efflux pump, and metabolism were differentially expressed. Collectively, our results provide an improved understanding of the response of P. aeruginosa to NaCl alternative compounds that can be implemented in fish-based products and encourage further exploration of the development of effective methods to protect foods against the P. aeruginosa, underestimate foodborne bacteria. Model studies describing the impact of salt substitutes and microaerophilic conditions used in minimally processed food technology, on the physiology and genetics of P. aeruginosa, a food spoilage microorganism.

Chemotherapy-induced peripheral neuropathy (CIPN) is a significant adverse event with unclear mechanisms and limited treatment alternatives. This study aimed to investigate the efficacy of two alkalizing agents, a mixture of potassium citrate and sodium citrate (K/Na citrate) or sodium bicarbonate (NaHCO3), in preventing and treating paclitaxel (PTX)-induced mechanical allodynia in rodents. The results from rodent models demonstrated that repeated prophylactic administration of K/Na citrate or NaHCO3 could inhibit the development of PTX-induced mechanical allodynia. Moreover, K/Na citrate was effective in preventing the PTX-induced exacerbation of mechanical allodynia, even when treatment was initiated immediately after the onset of allodynia. K/Na citrate also reduced the levels of the plasma complement component anaphylatoxin C3a in a PTX-induced CIPN rat model. Complement activation, resulting in the production of C3a, has been implicated in the pathogenesis of this model. Additionally, pretreatment with Na citrate significantly prevented the reduction in neurite outgrowth caused by PTX. Furthermore, K/Na citrate inhibited spontaneous and mechanical stimuli-induced firing in spinal dorsal horn neurons. These findings indicate that K/Na citrate may regulate the development of PTX-induced mechanical allodynia by modulating complement activation and providing neuroprotection against PTX-induced peripheral nerve injury. This study implies that alkalization could help prevent PTX-induced peripheral neuropathy and mitigate its exacerbation.

BACKGROUND: The sciatic nerve is a peripheral nerve and is more vulnerable to compression with subsequent short- or long-term neuronal dysfunction. The current study was designed to elucidate the possible ameliorative effect of L-carnitine and sildenafil (SIL) on sciatic nerve crush injury. We sought to determine the effects of L-carnitine, a neuroprotective and a neuro-modulatory agent, and SIL citrate, a selective peripheral phosphodiesterases inhibitor, on modulating neuro-degenerative changes due to sciatic nerve compression. MATERIALS AND METHODS: The comparative effect of L-carnitine (at an oral dose of 20 mg/kg/day) or SIL citrate (20 mg/kg/day orally) administration for 21 days was studied in a rat model of sciatic nerve compression. Sciatic nerve sections were subjected to biochemical, histological, ultrastructure, and immunohistochemical studies to observe the effects of these treatments on neurofilament protein. RESULTS: The sciatic nerve crush injury group (group II) showed a significant decrease in tissue catalase (CAT), superoxide dismutase (SOD) and increase in malondialdehyde (MDA) as compared to control group (p < 0.01). Histological changes in the form of degenerated and vacuolated axoplasm with areas of nerve fibre loss and pyknotic nuclei were reported. The blood vessels were dilated, congested with areas of haemorrhage and mononuclear cell infiltration. Histo-morphometrically, a statistically significant reduction in the nerve fibres’ number, mean axon cross-sectional area, myelin sheath thickness and a significant increase in collagen fibres’ percentage (p < 0.05) as compared to control group. Immunohistochemically, neurofilament protein was significantly downregulated as proved by a significant reduction in mean area per cent of neurofilament expression. L-carnitine ameliorated the studied parameters through its neuroprotective effect while SIL, a selective peripheral phosphodiesterases (PDE-5) inhibitor, improved crush injury parameters but with less extent than L-carnitine. CONCLUSIONS: These findings indicate the valuable effects of L-carnitine administration compared to that of SIL citrate in alleviating the serious debilitating effects of sciatic nerve crush injury. Our results provide a new insight into the scope of neuroprotective and neuro-regenerative effects of L-carnitine in a sciatic nerve compression model.

Both K and Ca supplementation may have beneficial effects on bone through separate mechanisms. K in the form of citrate or bicarbonate affects bone by neutralising the acid load caused by a high protein intake or a low intake of alkalising foods, i.e. fruits and vegetables. Ca is known to decrease serum parathyroid hormone (S-PTH) concentration and bone resorption. We compared the effects of calcium carbonate, calcium citrate and potassium citrate on markers of Ca and bone metabolism in young women. Twelve healthy women aged 22–30 years were randomised into four controlled 24 h study sessions, each subject serving as her own control. At the beginning of each session, subjects received a single dose of calcium carbonate, calcium citrate, potassium citrate or a placebo in randomised order. The diet during each session was identical, containing 300 mg Ca. Both the calcium carbonate and calcium citrate supplement contained 1000 mg Ca; the potassium citrate supplement contained 2250 mg K. Markers of Ca and bone metabolism were followed. Potassium citrate decreased the bone resorption marker (N-terminal telopeptide of type I collagen) and increased Ca retention relative to the control session. Both Ca supplements decreased S-PTH concentration. Ca supplements also decreased bone resorption relative to the control session, but this was significant only for calcium carbonate. No differences in bone formation marker (bone-specific alkaline phosphatase) were seen among the study sessions. The results suggest that potassium citrate has a positive effect on the resorption marker despite low Ca intake. Both Ca supplements were absorbed well and decreased S-PTH efficiently.

Like citrate, the molecule hydroxycitrate is shown to inhibit growth of the crystal that is the principal component of kidney stones, suggesting that hydroxycitrate could be another treatment for kidney stone disease. Novel inhibitor action on 'kidney stone' crystal growth This paper reports that both citrate and hydroxycitrate molecules are able to inhibit growth of crystals of calcium oxalate monohydrate — the principal component of kidney stones — even in a supersaturated solution where the inhibitor concentration is far smaller than the concentration of the solutes. The mechanism for crystal growth inhibition diverges from the classical picture of such processes: atomic force microscopy images and other data point to a mechanism in which inhibitor–crystal interactions impart localized strain to the crystal lattice that are alleviated by oxalate and calcium ions. Potassium citrate is an established treatment for kidney stone disease and the authors suggest that the clinical potential of hydroxycitrate might also be worth exploring and report preliminary in vitro investigations to support this suggestion. Crystalline materials are crucial to the function of living organisms, in the shells of molluscs 1 , 2 , 3 , the matrix of bone 4 , the teeth of sea urchins 5 , and the exoskeletons of coccoliths 6 . However, pathological biomineralization can be an undesirable crystallization process associated with human diseases 7 , 8 , 9 . The crystal growth of biogenic, natural and synthetic materials may be regulated by the action of modifiers, most commonly inhibitors, which range from small ions and molecules 10 , 11 to large macromolecules 12 . Inhibitors adsorb on crystal surfaces and impede the addition of solute, thereby reducing the rate of growth 13 , 14 . Complex inhibitor–crystal interactions in biomineralization are often not well elucidated 15 . Here we show that two molecular inhibitors of calcium oxalate monohydrate crystallization—citrate and hydroxycitrate—exhibit a mechanism that differs from classical theory in that inhibitor adsorption on crystal surfaces induces dissolution of the crystal under specific conditions rather than a reduced rate of crystal growth. This phenomenon occurs even in supersaturated solutions where inhibitor concentration is three orders of magnitude less than that of the solute. The results of bulk crystallization, in situ atomic force microscopy, and density functional theory studies are qualitatively consistent with a hypothesis that inhibitor–crystal interactions impart localized strain to the crystal lattice and that oxalate and calcium ions are released into solution to alleviate this strain. Calcium oxalate monohydrate is the principal component of human kidney stones 16 , 17 , 18 , 19 and citrate is an often-used therapy 20 , but hydroxycitrate is not. For hydroxycitrate to function as a kidney stone treatment, it must be excreted in urine. We report that hydroxycitrate ingested by non-stone-forming humans at an often-recommended dose leads to substantial urinary excretion. In vitro assays using human urine reveal that the molecular modifier hydroxycitrate is as effective an inhibitor of nucleation of calcium oxalate monohydrate nucleation as is citrate. Our findings support exploration of the clinical potential of hydroxycitrate as an alternative treatment to citrate for kidney stones.

Silver nanoparticles (AgNPs) have tremendous potentials in medical devices due to their excellent antimicrobial properties. Blood compatibility should be investigated for AgNPs due to the potential blood contact. However, so far, most studies are not systematic and have not provided insights into the mechanisms for blood compatibility of AgNPs. In this study, we have investigated the blood biological effects, including hemolysis, lymphocyte proliferation, platelet aggregation, coagulation and complement activation, of 20 nm AgNPs with two different surface coatings (polyvinyl pyrrolidone and citrate). Our results have revealed AgNPs could elicit hemolysis and severely impact the proliferation and viability of lymphocytes at all investigated concentrations (10, 20, 40 μg/mL). Nevertheless, AgNPs didn’t show any effect on platelet aggregation, coagulation process, or complement activation at up to ~40 μg/mL. Proteomic analysis on AgNPs plasma proteins corona has revealed that acidic and small molecular weight blood plasma proteins were preferentially adsorbed onto AgNPs, and these include some important proteins relevant to hemostasis, coagulation, platelet, complement activation and immune responses. The predicted biological effects of AgNPs by proteomic analysis are mostly consistent with our experimental data since there were few C3 components on AgNPs and more negative than positive factors involving platelet aggregation and thrombosis.

Background Astrocytes are crucial regulators in the central nervous system. Abnormal activation of astrocytes contributes to some behavior deficits. However, mechanisms underlying the effects remain unclear. Here, we studied the activation of A1 astrocytes and their contribution to murine behavior deficits. Methods A1 astrocytes were induced by treatment with lipopolysaccharide (LPS) in vitro. The functional phenotype of astrocytes was determined by quantitative RT-PCR, ELISA, and immunohistochemistry. To assess the role of A1 astrocytes in vivo, mice were injected intraperitoneally with LPS. Then, murine behaviors were tested, and the hippocampus and cortex were analyzed by quantitative RT-PCR, ELISA, and immunohistochemistry. The function of IL-10 and fluorocitrate on A1 astrocyte activation was also examined. Results Our results show that astrocytes isolated from B6.129S6-Il10 tm1Flv /J homozygotes (IL-10 tm1/tm1 ) were prone to characteristics of A1 reactive astrocytes. Compared with their wild-type counterparts, IL-10 tm1/tm1 astrocytes exhibited higher expression of glial fibrillary acidic protein (GFAP). Whether or not they were stimulated with LPS, IL-10 tm1/tm1 astrocytes exhibited enhanced expression of A1-specific transcripts and proinflammatory factors IL-1β, IL-6, and TNFα. In addition, IL-10 tm1/tm1 astrocytes demonstrated hyperphosphorylation of STAT3. Moreover, astrocytes from IL-10 tm1/tm1 mice showed attenuated phagocytic ability and were neurotoxic. IL-10 tm1/tm1 mice demonstrated increased immobility time in the forced swim test and defective learning and memory behavior in the Morris water maze test. Moreover, enhanced neuroinflammation was found in the hippocampus and cortex of IL-10 tm1/tm1 mice, accompanying with more GFAP-positive astrocytes and severe neuron loss in the hippocampus. Pretreatment IL-10 tm1/tm1 mice with IL-10 or fluorocitrate decreased the expression of proinflammatory factors and A1-specific transcripts in the hippocampus and cortex, and then alleviated LPS-induced depressive-like behavior. Conclusion These results demonstrate that astrocytes isolated from B6.129S6-Il10 tm1Flv /J homozygotes are prone to A1 phenotype and contribute to the depression-like behavior and memory deficits. Inhibiting A1 astrocyte activation may be an attractive therapeutic strategy in some neurodegenerative diseases.

Faced with skyrocketing costs for developing new drugs, researchers are looking at ways to repurpose older ones — and even some that failed in initial trials.

The biocidal properties of silver nanoparticles (AgNPs) prepared with the use of biologically active compounds seem to be especially significant for biological and medical application. Therefore, the aim of this research was to determine and compare the antibacterial and fungicidal properties of fifteen types of AgNPs. The main hypothesis was that the biological activity of AgNPs characterized by comparable size distributions, shapes, and ion release profiles is dependent on the properties of stabilizing agent molecules adsorbed on their surfaces. Escherichia coli and Staphylococcus aureus were selected as models of two types of bacterial cells. Candida albicans was selected for the research as a representative type of eukaryotic microorganism. The conducted studies reveal that larger AgNPs can be more biocidal than smaller ones. It was found that positively charged arginine-stabilized AgNPs (ARGSBAgNPs) were the most biocidal among all studied nanoparticles. The strongest fungicidal properties were detected for negatively charged EGCGAgNPs obtained using (−)-epigallocatechin gallate (EGCG). It was concluded that, by applying a specific stabilizing agent, one can tune the selectivity of AgNP toxicity towards desired pathogens. It was established that E. coli was more sensitive to AgNP exposure than S. aureus regardless of AgNP size and surface properties.

The gold standard treatment for apnea of prematurity is caffeine citrate, which is known for its effect on diaphragm muscle activity. The purpose of this study was to investigate the electrical activity of the diaphragm in preterm newborns, which was measured 30 minutes before and 60 minutes after the administration of a loading dose of caffeine citrate. In this prospective, observational, longitudinal study at a tertiary-level neonatal ICU, data were collected from 36 patients (13 females, 23 males) with a mean gestational age of 31 2/7 ± 2 1/7 weeks and a mean birth weight of 1532 ± 439 grams. The average caffeine level was 15.7 ± 5.9 mg/dL (reference range: 5–30 mg/dL). The results revealed significant increases in all the parameters used to determine the inspiratory phases of the respiratory cycle postcaffeine administration (p < 0.001). The study concluded that caffeine administration significantly enhances diaphragmatic electrical activity in preterm newborns.