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European Review For Medical and... Nov 2022Elevation in blood glucose is common in COVID-19 patients. There is also a high incidence of new-onset diabetes mellitus (DM) in COVID-19 patients following... (Review)
Review
Elevation in blood glucose is common in COVID-19 patients. There is also a high incidence of new-onset diabetes mellitus (DM) in COVID-19 patients following hospitalization. To date, the underlying cause(s) for the hyperglycemia and new-onset DM post-COVID-19 remain poorly understood. In this narrative review, we suggest that upregulation of the cytotoxic and diffusible glycolytic byproduct methylglyoxal (MGO) arising from increased glycolysis in infected pancreatic islets, macrophages, and peripheral cells/tissues is impairing insulin production, secretion, and signaling. This hypothesis is based on our recent discovery that MGO levels were elevated in the plasma of hospitalized COVID-19 patients without and with DM and even higher in COVID-19 patients that succumb to the disease. In pancreatic islets infected with SARS-CoV-2, elevated MGO will disrupt mitochondrial function, perturb Ca2+ homeostasis, and activate the receptors for advanced glycation end-product (RAGE) and nuclear factor kappa B (NF-kB) resulting in impaired insulin production and secretion. In macrophages, excess MG production can diffuse into the vasculature disrupting endothelial function and triggering micro/macro hemorrhage, ischemia, and tissue fibrosis. In skeletal muscle and liver cells, MGO disruption of insulin signaling can blunt glucose absorption. Metformin and N-acetyl cysteine have recently been shown to decrease morbidity and mortality in COVID-19 patients. Here we propose that these agents may be exerting their beneficial effects by chemically reacting with and lowering MGO levels. Knowledge gained from this review should provide novel mechanistic insights for hyperglycemia in COVID-19 patients and strategies to blunt the development of new-onset of DM in post-COVID patients.
Topics: Humans; Pyruvaldehyde; COVID-19; Magnesium Oxide; SARS-CoV-2; Hyperglycemia; Diabetes Mellitus; Insulin
PubMed: 36394765
DOI: 10.26355/eurrev_202211_30169 -
RSC Advances Sep 2023We investigate Raman spectra (100 cm to 3900 cm) of magnesium oxide nanoparticles with nominal sizes of 10 nm, 20 nm, 40 nm, 50 nm, and 300 nm. The crystal structure of...
We investigate Raman spectra (100 cm to 3900 cm) of magnesium oxide nanoparticles with nominal sizes of 10 nm, 20 nm, 40 nm, 50 nm, and 300 nm. The crystal structure of MgO prohibits first-order modes and yet, there are numerous reports of relatively intense peaks throughout the literature. Raman signals at approximately 278 cm and 445 cm that were attributed to MgO nanoparticles by previous authors are shown to belong to layers of Mg(OH) formed on the surface of MgO nanoparticles. Through an annealing process at 400 °C in an O atmosphere, we observe that modes in the 3700 cm spectral region, which are a signature of OH groups, disappear together with modes at 278 cm and 445 cm, thus establishing a necessary criterion to associate all of these peaks to the presence of OH groups on the surface.
PubMed: 37681036
DOI: 10.1039/d3ra04492k -
International Journal of Nanomedicine 2019Recently, nanomaterials have moved into biological and medicinal implementations like cancer therapy. Therefore, before clinical trials, their binding to plasma proteins...
BACKGROUND
Recently, nanomaterials have moved into biological and medicinal implementations like cancer therapy. Therefore, before clinical trials, their binding to plasma proteins like human serum albumin (HSA) and their cytotoxic effects against normal and cancer cell lines should be addressed.
METHODS
Herein, the interaction of magnesium oxide nanoparticles (MgO NPs) with HSA was studied by means of fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and docking studies. Afterwards, the cytotoxic impacts of MgO NPs on human leukemia cell line (K562) and peripheral blood mononucleated cells (PBMCs) were evaluated by MTT and flow cytometry assays to quantify reactive oxygen species (ROS) generation and apoptosis.
RESULTS
It was demonstrated that MgO NPs spontaneously form a static complex with HSA molecules through hydrophobic interactions. Docking study based on the size of NPs demonstrated that different linkages can be established between MgO NPs and HSA. The CD investigation explored that MgO NPs did not alter the secondary structure of HSA. Cellular studies revealed that MgO NPs induced cytotoxicity against K562 cell lines, whereas no adverse effects were detected on PBMCs up to optimum applied concentration of MgO NPs. It was exhibited that ROS production mediated by IC50 concentrations of MgO NPs caused apoptosis-associated cell death. The pre-incubation of K562 with ROS scavenger (curcumin) inhibited the impact of MgO NPs -based apoptosis on cell fate, revealing the upstream effect of ROS in our system.
CONCLUSION
In summary, MgO NPs may exhibit strong plasma distribution and mediate apoptosis by ROS induction in the cancer cell lines. These data demonstrate a safe aspect of MgO NPs on the proteins and normal cells and their application as a distinctive therapeutic approach in the cancer treatment.
Topics: Cell Proliferation; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Magnesium Oxide; Metal Nanoparticles; Molecular Docking Simulation; Protein Conformation; Serum Albumin, Human; Tumor Cells, Cultured
PubMed: 30643405
DOI: 10.2147/IJN.S186428 -
Digestion 2024The prevalence of constipation in Japan is estimated to be 2-5%. Constipation is a disease found in older adults. In particular, Japan is an aging society, with 65% of... (Review)
Review
BACKGROUND
The prevalence of constipation in Japan is estimated to be 2-5%. Constipation is a disease found in older adults. In particular, Japan is an aging society, with 65% of men and 80.5% of women aged 65 years or older accounting for the majority of its population. Chronic constipation may be associated with survival, cardiovascular events, decreased quality of life, and death. This study summarizes the recent findings regarding constipation treatment practice in Japan.
SUMMARY
Until recently, the diagnosis of constipation was mainly based on medical interviews; however, with the recent development of handheld ultrasound devices, both physicians and nurses can easily and objectively diagnose fecal retention. Magnesium oxide and stimulant laxatives have been the mainstay treatments; however, since 2012, more than five new drugs for treating constipation have become available in Japan.
KEY MESSAGES
Magnesium oxide is less effective in patients who use acid-secretion inhibitors and patients who have undergone total gastrectomy and should be cared for hypermagnesemia. In addition, regular use of stimulant laxatives may lead to colonic inertia and decreased bowel movements; therefore, they should be used only occasionally. The following is an overview of the different uses of conventional and newer laxatives for treating constipation.
Topics: Male; Humans; Female; Aged; Laxatives; Magnesium Oxide; Japan; Quality of Life; Constipation
PubMed: 37696258
DOI: 10.1159/000533548 -
Materials (Basel, Switzerland) Jul 2021Many scholars are concerned about the effect of nano-MgO as an expansion agent on the performance of cement-based materials at an early age, but over a long period less...
Many scholars are concerned about the effect of nano-MgO as an expansion agent on the performance of cement-based materials at an early age, but over a long period less attention is paid to expansion stability and mechanical properties. This article examines the influence of nano-MgO on the long-term consistency, fluidity, expansion stability, hydration, and mechanical properties of 30% fly ash cement-based materials and improves research into nano-MgO as an expansion agent. Expansion performance, flexural and compressive strength, and stability after boiling and autoclave treatment were tested for specimens mixed with a 2, 4, 6, 8 and 10% cementitious material mass of nano-MgO. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) were employed to study their hydration process and microstructure. The results showed that nano-MgO had an obvious effect on the consistency, fluidity and expansion performance of cement paste. After curing in water for 365 days and autoclaving thereafter, the hydration of nano-MgO was relatively complete. The volumetric expansion pressure of the magnesium hydroxide (Mg(OH)) crystals and the crystallization pressure generated after their continuous precipitation were the main reasons for the expansion of the slurry. Nano-MgO improved the microstructure of cement paste and significantly enhanced its long-term flexural strength and compressive strength. When the content of nano-MgO was less than 10%, the cement with 30% fly ash had good long-term stability with the potential to compensate for the shrinkage of large-volume concrete.
PubMed: 34279336
DOI: 10.3390/ma14133766 -
Nutrients Jul 2020Functional constipation (FC) is a chronic constipation for which no physiological, anatomical or iatrogenic origin can be evidenced. This condition has a high impact on... (Review)
Review
Functional constipation (FC) is a chronic constipation for which no physiological, anatomical or iatrogenic origin can be evidenced. This condition has a high impact on a patient's quality of life and healthcare costs. Since FC is frequently associated with low physical activity and a diet low in fiber and/or water, first-line recommendations focus on sufficient activity, and sufficient fiber and water intake. In case of inefficacy of these measures, numerous drug treatments are available, either over the counter or on prescription. Magnesium sulfate has a long history in the treatment of FC, and magnesium sulfate-rich mineral waters have been used for centuries for their laxative properties. The laxative effect of magnesium and sulfate has since been widely demonstrated. Nevertheless, it appears that no clinical studies aiming at demonstrating their efficacy in FC had been conducted before the 21st century. In this paper, we reviewed the clinical data reporting the efficacy of magnesium sulfate-rich natural mineral waters. In view of their reported efficacy and safety, magnesium sulfate-rich natural mineral waters may represent a natural treatment for FC.
Topics: Constipation; Defecation; Dietary Fiber; Female; Humans; Laxatives; Magnesium Oxide; Magnesium Sulfate; Male; Mineral Waters; Probiotics; Quality of Life
PubMed: 32664341
DOI: 10.3390/nu12072052 -
Materials (Basel, Switzerland) Aug 2022Materials with violent hydration reaction such as cement are used to solidify sandy soil slopes, which will cause destructive damage to the ecology of the slopes. In...
Materials with violent hydration reaction such as cement are used to solidify sandy soil slopes, which will cause destructive damage to the ecology of the slopes. In this paper, polyvinyl alcohol (PVA) and activated magnesium oxide (MgO) are used to improve sandy soil, and the effects of the dosage and curing age of modifiers on the mechanical properties of solidified sandy soil are studied. The dry-wet durability of the composite improved sandy soil is analyzed using a dry-wet cycle test, and the improvement mechanism of PVA and activated magnesium oxide is revealed using an electron microscope. The results show that the curing effect of polyvinyl alcohol and activated magnesium oxide on sand particles is better than that of polyvinyl alcohol alone. The compressive strength of improved soil samples increases with the increase of curing time, and magnesium oxide as an improved material needs appropriate reaction conditions to give full play to its role. The compressive strength of composite improved samples increases first and then decreases during the dry-wet cycle. Through the observation of microstructure, it can be seen that the cementing material wraps and connects the sand particles, and the cementing material of the sample after the dry-wet cycle develops more completely; if the magnesium oxide content is high, cracks may appear inside the sample.
PubMed: 36013746
DOI: 10.3390/ma15165609 -
BMJ Supportive & Palliative Care Jan 2024The initiation of peripherally acting μ-opioid receptor antagonists (PAMORAs) should be considered 2 weeks after conventional laxatives have failed to achieve an...
OBJECTIVES
The initiation of peripherally acting μ-opioid receptor antagonists (PAMORAs) should be considered 2 weeks after conventional laxatives have failed to achieve an adequate response, and affected patients should be evaluated every 2 weeks thereafter. However, this guidance is difficult to implement in acute care hospitals. This study aimed to examine how naldemedine (PAMORA) should be introduced in combination with other laxatives in the acute care setting.
METHODS
This retrospective study evaluated 93 inpatients who received at least four doses of naldemedine. We investigated changes in the average daily defecation counts during the first 7 days after compared with before naldemedine administration and the incidence of diarrhoea.
RESULTS
Daily defecation counts during the first 7 days after compared with before naldemedine administration were greater in both the naldemedine, magnesium oxide (MgO) and another laxative group, and in the naldemedine and another laxative other than MgO group than in the naldemedine only group. The incidence rates of diarrhoea were significantly higher in the naldemedine, MgO, and another laxative group, and in the naldemedine and another laxative other than MgO group than in the naldemedine only group.
CONCLUSIONS
The introduction of naldemedine alone or in combination with MgO should be considered.
Topics: Humans; Laxatives; Retrospective Studies; Magnesium Oxide; Inpatients; Analgesics, Opioid; Constipation; Naltrexone; Narcotic Antagonists; Diarrhea
PubMed: 35750467
DOI: 10.1136/spcare-2022-003685 -
Redox Biology Aug 2023Diabetic retinopathy (DR) is a major cause of blindness in adult, and the accumulation of advanced glycation end products (AGEs) is a major pathologic event in DR....
Metformin inhibits methylglyoxal-induced retinal pigment epithelial cell death and retinopathy via AMPK-dependent mechanisms: Reversing mitochondrial dysfunction and upregulating glyoxalase 1.
Diabetic retinopathy (DR) is a major cause of blindness in adult, and the accumulation of advanced glycation end products (AGEs) is a major pathologic event in DR. Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is a precursor of AGEs. Although the therapeutic potential of metformin for retinopathy disorders has recently been elucidated, possibly through AMPK activation, it remains unknown how metformin directly affects the MGO-induced stress response in retinal pigment epithelial cells. Therefore, in this study, we compared the effects of metformin and the AMPK activator A769662 on MGO-induced DR in mice, as well as evaluated cytotoxicity, mitochondrial dynamic changes and dysfunction in ARPE-19 cells. We found MGO can induce mitochondrial ROS production and mitochondrial membrane potential loss, but reduce cytosolic ROS level in ARPE-19 cells. Although these effects of MGO can be reversed by both metformin and A769662, we demonstrated that reduction of mitochondrial ROS production rather than restoration of cytosolic ROS level contributes to cell protective effects of metformin and A769662. Moreover, MGO inhibits AMPK activity, reduces LC3II accumulation, and suppresses protein and gene expressions of MFN1, PGC-1α and TFAM, leading to mitochondrial fission, inhibition of mitochondrial biogenesis and autophagy. In contrast, these events of MGO were reversed by metformin in an AMPK-dependent manner as evidenced by the effects of compound C and AMPK silencing. In addition, we observed an AMPK-dependent upregulation of glyoxalase 1, a ubiquitous cellular enzyme that participates in the detoxification of MGO. In intravitreal drug-treated mice, we found that AMPK activators can reverse the MGO-induced cotton wool spots, macular edema and retinal damage. Functional, histological and optical coherence tomography analysis support the protective actions of both agents against MGO-elicited retinal damage. Metformin and A769662 via AMPK activation exert a strong protection against MGO-induced retinal pigment epithelial cell death and retinopathy. Therefore, metformin and AMPK activator can be therapeutic agents for DR.
Topics: Mice; Animals; Metformin; AMP-Activated Protein Kinases; Pyruvaldehyde; Reactive Oxygen Species; Magnesium Oxide; Lactoylglutathione Lyase; Mitochondria; Retinal Diseases; Glycation End Products, Advanced; Epithelial Cells; Retinal Pigments
PubMed: 37348156
DOI: 10.1016/j.redox.2023.102786 -
Micromachines Nov 2022This research was conducted for the synthesis and application of ophthalmic lens materials with improved oxygen permeability and durability. Polyvinylpyrrolidone (PVP),...
This research was conducted for the synthesis and application of ophthalmic lens materials with improved oxygen permeability and durability. Polyvinylpyrrolidone (PVP), N-vinyl-2-pyrrolidone (NVP), 3-(trifluoromethyl)styrene (3-TFMSt), and magnesium oxide nanoparticles were used as additives for the basic combination of 2-hydroxyethyl methacrylate (HEMA). Additionally, the materials were copolymerized with ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent and azobisisobutyronitrile (AIBN) as the initiator. The addition of magnesium oxide nanoparticles was found to increase the tensile strength from 0.0631 to 0.0842 kgf/mm. Copolymerization with a small amount of 3-TFMSt of about 1% increased the tensile strength to 0.1506 kgf/mm and the oxygen permeability from 6.00 to 9.64 (cm/s)∙(mLO/mL·mmHg)∙10. The contact lens material produced using N-vinyl-2-pyrrolidone and magnesium oxide nanoparticles as additives satisfied the basic physical properties required for hydrogel contact lenses and is expected to be used usefully as a material for fabricating high-performance hydrogel lenses.
PubMed: 36363917
DOI: 10.3390/mi13111897