scholarly journals Hydrogen Peroxide Levels in Freshly Brewed Coffee and the Effects of Storage

2020 ◽  
Author(s):  
Sannihith N. Uppu ◽  
Bianca K. London
Keyword(s):  
Hydrogen Peroxide ◽  
Xylenol Orange ◽  
Cell Types ◽  
Toxic Effects ◽  
Temperature Dependent ◽  
General Belief ◽  
Cytotoxic Effects ◽  
Future Studies ◽  
Aging Phenomenon ◽  
Fox Assay

SummaryOne of the world’s most consumed beverages, coffee has its origins as early as the 15th century Ethiopia. Although there are studies on caffeine and other components of coffee such as cafestol and kahweol, up until recently knowledge of the presence of hydrogen peroxide (H2O2) in coffee was confined to the scientific community and some informed public. It is a general belief that H2O2 is formed only after long periods of storage or with certain roasting practices. The present study is focused on dispelling the myths of H2O2 in coffee. We first measured H2O2 in freshly brewed coffee from different companies using the ferrous oxidation-xylenol orange binding (FOX) assay. Following this, we examined the time-dependent accumulation of H2O2 and its changes with temperature. Further, H2O2 was estimated in coffee obtained from several local vendors. Contrary to the general belief that the accumulation of H2O2 is an aging phenomenon of coffee, we found this toxicant even in freshly brewed coffee. This was true for all brands tested, and the H2O2 content increased upon storage. The highest increase was seen in coffee stored on the hot plate compared to the ones kept at room temperature (22-25 °C) or in the cold (0-4 °C). The H2O2 content of coffee from different vendors ranged between 0.29 and 0.82 mM, which is 5- to 20-fold higher than the typical H2O2 concentrations at which significant cytotoxic effects have been reported for assay systems using the human Fanconi deficient (PD20 FANCD2−/−) fibroblasts and other cell types. Our findings are deemed to shine new light on the probable toxic effects of a commonly consumed beverage like coffee, and the time and temperature dependent variations of keeping. While there are documented benefits of consumption of coffee, the possible H2O2-medicated toxic effects are critical and should be considered. Future studies are warranted to delineate the contribution of H2O2 in the healthy wellbeing of individuals who consume coffee extensively.

scholarly journals Factors Contributing to Hydrogen Peroxide Resistance in Streptococcus pneumoniae Include Pyruvate Oxidase (SpxB) and Avoidance of the Toxic Effects of the Fenton Reaction

2003 ◽  
Vol 185 (23) ◽  
pp. 6815-6825 ◽  
Author(s):  
Christopher D. Pericone ◽  
Sunny Park ◽  
James A. Imlay ◽  
Jeffrey N. Weiser
Keyword(s):  
Hydrogen Peroxide ◽  
Streptococcus Pneumoniae ◽  
Fenton Reaction ◽  
Bacterial Species ◽  
Atp Depletion ◽  
Host Cells ◽  
Toxic Effects ◽  
Aerobic Growth ◽  
Pyruvate Oxidase ◽  
Cytotoxic Effects

ABSTRACT Aerobic growth of Streptococcus pneumoniae results in production of amounts of hydrogen peroxide (H2O2) that may exceed 1 mM in the surrounding media. H2O2 production by S. pneumoniae has been shown to kill or inhibit the growth of other respiratory tract flora, as well as to have cytotoxic effects on host cells and tissue. The mechanisms allowing S. pneumoniae, a catalase-deficient species, to survive endogenously generated concentrations of H2O2 that are sufficient to kill other bacterial species is unknown. In the present study, pyruvate oxidase (SpxB), the enzyme responsible for endogenous H2O2 production, was required for survival during exposure to high levels (20 mM) of exogenously added H2O2. Pretreatment with H2O2 did not increase H2O2 resistance in the mutant, suggesting that SpxB activity itself is required, rather than an H2O2-inducible pathway. SpxB mutants synthesized 85% less acetyl-phosphate, a potential source of ATP. During H2O2 exposure, ATP levels decreased more rapidly in spxB mutants than in wild-type cells, suggesting that the increased killing of spxB mutants was due to more rapid ATP depletion. Together, these data support the hypothesis that S. pneumoniae SpxB contributes to an H2O2-resistant energy source that maintains viability during oxidative stress. Thus, SpxB is required for resistance to the toxic by-product of its own activity. Although H2O2-dependent hydroxyl radical production and the intracellular concentration of free iron were similar to that of Escherichia coli, killing by H2O2 was unaffected by iron chelators, suggesting that S. pneumoniae has a novel mechanism to avoid the toxic effects of the Fenton reaction.

Cytotoxic Effects of Hydrogen Peroxide on Human Gingival Fibroblasts In Vitro

2015 ◽  
Vol 40 (4) ◽  
pp. 430-439 ◽  
Author(s):  
M Furukawa ◽  
Jr K-Kaneyama ◽  
M Yamada ◽  
A Senda ◽  
A Manabe ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Vitamin E ◽  
Survival Rates ◽  
Human Gingival Fibroblasts ◽  
Toxic Effects ◽  
Bleaching Agent ◽  
Gingival Fibroblasts ◽  
Cytotoxic Effects ◽  
Peripheral Tissues ◽  
Tnf Α

SUMMARY In-office bleaching is a popular treatment in modern esthetic dentistry. However, bleaching agents sometimes accidentally adhere to the gingiva and peripheral tissues, even when applied by well-trained dentists. This can lead to transient pain and whitish changes in the gingiva. Although these symptoms disappear within several hours, the effects of bleaching agents on gingiva have not been well described in the literature. The present study aimed to elucidate the cytotoxic effects of a bleaching agent on cultured human gingival fibroblasts (HGFs). We performed a comprehensive analysis of the toxic effects of in-office bleaching agents on gingiva using cultured HGFs and DNA microarray. Survival rates of HGFs decreased with increases in the concentration of hydrogen peroxide, which became significant at concentrations of 1.5 × 10−3% or higher at every time point. Concentrations lower than 1.5 × 10−3% did not affect survival rates of HGFs. Cytotoxicity of hydrogen peroxide was significantly weakened by the addition of vitamin E. Stimulation by in-office bleaching agents triggered the proinflammatory cytokine tumor necrosis factor (TNF)–α cascade in gingival fibroblasts. As the TNF-α cascade can be inhibited by vitamin E additives, treatment with vitamin E may protect gingival fibroblasts against the toxic effects of an in-office bleaching agent. The present results suggest that local administration of vitamin E to gingiva before in-office bleaching may be useful for preventing gingival irritation due to accidental adhesion of a bleaching agent.

Xylenol-orange-assay-of-hydrogen-peroxide for Measuring Uricase Activity and Recognizing High-activity Uricase Mutant

2013 ◽  
Vol 19 (3) ◽  
pp. 523-527 ◽  
Author(s):  
Miaomiao LIU ◽  
Juan FENG ◽  
Hongbo LIU ◽  
Xiaolan YANG ◽  
Liping FENG ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
High Activity ◽  
Xylenol Orange ◽  
Uricase Activity

scholarly journals Expression of SOX2 and OCT4 in odontogenic cysts and tumors

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Ekarat Phattarataratip ◽  
Tarit Panitkul ◽  
Watunyoo Khodkaew ◽  
Pattarapong Anupuntanun ◽  
Jirapat Jaroonvechatam ◽  
...  
Keyword(s):  
Cell Types ◽  
Odontogenic Cysts ◽  
Positive Staining ◽  
Stem Cell Markers ◽  
Aberrant Expression ◽  
Future Studies ◽  
Sox2 Expression ◽  
Cells Of Origin ◽  
Dentigerous Cysts ◽  
Patient Prognosis

Abstract Background Aberrant expression of stem cell markers has been observed in several types of neoplasms. This trait attributes to the acquired stem-like property of tumor cells and can impact patient prognosis. The objective of this study was to comparatively analyze the expression and significance of SOX2 and OCT4 in various types of odontogenic cysts and tumors. Methods Fifty-five cases of odontogenic cysts and tumors, including 15 ameloblastomas (AM), 5 adenomatoid odontogenic tumors (AOT), 5 ameloblastic fibromas (AF), 5 calcifying odontogenic cysts (COC), 10 dentigerous cysts (DC) and 15 odontogenic keratocysts (OKC) were investigated for the expression of SOX2 and OCT4 immunohistochemically. Results Most OKCs (86.7 %) and all AFs expressed SOX2 in more than 50 % of epithelial cells. Its immunoreactivity was moderate-to-strong in all epithelial cell types in both lesions. In contrast, SOX2 expression was undetectable in AOTs and limited to the ameloblast-like cells in a minority of AM and COC cases. Most DCs showed positive staining in less than 25 % of cystic epithelium. Significantly greater SOX2 expression was noted in OKC compared with DC or AM, and in AF compared with COC or AOT. OCT4 rarely expressed in odontogenic lesions with the immunoreactivity being mild and present exclusively in OKCs. Conclusions SOX2 is differentially expressed in odontogenic cysts and tumors. This could be related to their diverse cells of origin or stages of histogenesis. The overexpression of SOX2 and OCT4 in OKC indicates the acquired stem-like property. Future studies should investigate whether the overexpression of OCT4 and SOX2 contributes to the aggressive behaviors of the tumors.

scholarly journals Plasma IL-6 levels following corticosteroid therapy as an indicator of ICU length of stay in critically ill COVID-19 patients

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Samir Awasthi ◽  
Tyler Wagner ◽  
A. J. Venkatakrishnan ◽  
Arjun Puranik ◽  
Matthew Hurchik ◽  
...  
Keyword(s):  
Distress Syndrome ◽  
Cell Types ◽  
Specific Cell ◽  
Cytokine Release ◽  
Cytokine Release Syndrome ◽  
Rna Seq ◽  
Future Studies ◽  
Icu Length Of Stay ◽  
Potential Association ◽  
Clinical Trial Results

AbstractIntensive care unit (ICU) admissions and mortality in severe COVID-19 patients are driven by “cytokine storms” and acute respiratory distress syndrome (ARDS). Interim clinical trial results suggest that the corticosteroid dexamethasone displays better 28-day survival in severe COVID-19 patients requiring ventilation or oxygen. In this study, 10 out of 16 patients (62.5%) that had an average plasma IL-6 value over 10 pg/mL post administration of corticosteroids also had worse outcomes (i.e., ICU stay >15 days or death), compared to 8 out of 41 patients (19.5%) who did not receive corticosteroids (p-value = 0.0024). Given this potential association between post-corticosteroid IL-6 levels and COVID-19 severity, we hypothesized that the glucocorticoid receptor (GR or NR3C1) may be coupled to IL-6 expression in specific cell types that govern cytokine release syndrome (CRS). Examining single-cell RNA-seq data from BALF of severe COVID-19 patients and nearly 2 million cells from a pan-tissue scan shows that alveolar macrophages, smooth muscle cells, and endothelial cells co-express NR3C1 and IL-6, motivating future studies on the links between the regulation of NR3C1 function and IL-6 levels.

scholarly journals Protective Role of Flavonoids against Intestinal Pro-Inflammatory Effects of Silver Nanoparticles

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6610
Author(s):  
Ana T. Rufino ◽  
Ana Ramalho ◽  
Adelaide Sousa ◽  
José Miguel P. Ferreira de Oliveira ◽  
Paulo Freitas ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Protective Action ◽  
Cell Types ◽  
Protective Role ◽  
Toxic Effects ◽  
Oral Exposure ◽  
Dietary Flavonoids ◽  
Harmful Effects ◽  
Human Intestinal Cells

Silver nanoparticles (AgNP) have been increasingly incorporated into food-related and hygiene products for their unique antimicrobial and preservative properties. The consequent oral exposure may then result in unpredicted harmful effects in the gastrointestinal tract (GIT), which should be considered in the risk assessment and risk management of these materials. In the present study, the toxic effects of polyethyleneimine (PEI)-coated AgNP (4 and 19 nm) were evaluated in GIT-relevant cells (Caco-2 cell line as a model of human intestinal cells, and neutrophils as a model of the intestinal inflammatory response). This study also evaluated the putative protective action of dietary flavonoids against such harmful effects. The obtained results showed that AgNP of 4 and 19 nm effectively induced Caco-2 cell death by apoptosis with concomitant production of nitric oxide, irrespective of the size. It was also observed that AgNP induced human neutrophil oxidative burst. Interestingly, some flavonoids, namely quercetin and quercetagetin, prevented the deleterious effects of AgNP in both cell types. Overall, the data of the present study provide a first insight into the promising protective role of flavonoids against the potentially toxic effects of AgNP at the intestinal level.

scholarly journals Toxic effects of oxygen and of hydrogen peroxide on brain metabolism

1946 ◽  
Vol 40 (1) ◽  
pp. 139-144 ◽  
Author(s):  
P. J. G. Mann ◽  
J. H. Quastel
Keyword(s):  
Hydrogen Peroxide ◽  
Brain Metabolism ◽  
Toxic Effects

Description of the gastrointestinal tract and associated organs of the kultarr (Antechinomys laniger)

2013 ◽  
Vol 35 (1) ◽  
pp. 39 ◽  
Author(s):  
Hayley J. Stannard ◽  
Julie M. Old
Keyword(s):  
Gastrointestinal Tract ◽  
Digestive Tract ◽  
Large Intestine ◽  
Cell Types ◽  
Post Mortem ◽  
Microscopic Description ◽  
Future Studies ◽  
New Information ◽  
Small And Large Intestine

This paper provides a macro- and microscopic description of the digestive tract of the kultarr (Antechinomys laniger), a small dasyurid marsupial. The digestive tract was simple, with no external differentiation between the small and large intestine, and lacked a caecum. Mean gross length of the kultarr digestive tract was 165.2 ± 32.1 mm. Microscopically, the tissues had cell types similar to those of other mammals. The new information will aid future post-mortem investigations of captive kultarrs and future studies of nutrition.

scholarly journals Icaritin: A Novel Natural Candidate for Hematological Malignancies Therapy

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Xiao-Jing Yang ◽  
Ya-Ming Xi ◽  
Zi-Jian Li
Keyword(s):  
Hematological Malignancies ◽  
Treatment Options ◽  
Chinese Herb ◽  
Cell Types ◽  
Hematologic Malignancies ◽  
Cytotoxic Effects ◽  
Novel Treatment ◽  
Traditional Chinese Herb ◽  
Current Therapies ◽  
Underlying Mechanisms

Hematological malignancies including leukemia and lymphoma can severely impact human health. With the current therapies combined with chemotherapy, stem cell transplantation, radiotherapy, and immunotherapy, the prognosis of hematologic malignancies improved significantly. However, most hematological malignancies are still incurable. Therefore, research for novel treatment options was continuing with the natural product as one source. Icaritin is a compound extracted from a traditional Chinese herb,Epimedium Genus, and demonstrated an antitumor effect in various neoplasms including hematological malignancies such as leukemia, lymphoma, and multiple myeloma. In hematological malignancies, icaritin showed multiple cytotoxic effects to induce apoptosis, arrest the cell cycle, inhibit proliferation, promote differentiation, restrict metastasis and infiltration, and suppress the oncogenic virus. The proved underlying mechanisms of the cytotoxic effects of icaritin are different in various cell types of hematological malignancies but associated with the critical cell signal pathway, including PI3K/Akt, JAK/STAT3, and MAPK/ERK/JNK. Although the primary target of icaritin is still unspecified, the existing evidence indicates that icaritin is a potential novel therapeutic agent for neoplasms as with hematological malignancies. Here, in the field of hematology, we reviewed the reported activity of icaritin in hematologic malignancies and the underlying mechanisms and recognized icaritin as a candidate for therapy of hematological malignancies.

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