Addition Of Caffeine Research Articles

Effects of Caffeine Doses on Rumen Fermentation Profile and Nutrient Digestibility Using a Lactating Cow Diet under Continuous Cultures Conditions

Caffeine is a plant secondary metabolite, commonly known for its bioactivity properties. This molecule increases microbial activity during anaerobic digestion. The aim of this study was to determine the effects of caffeine doses on the rumen fermentation profile and nutrient digestibility when continuous culture fermenters were fed a lactating cow’s diet. We hypothesize that adding caffeine doses into continuous culture fermenters with a rumen fluid inoculum will not affect anaerobic fermentation or nutrient utilization. Fermenters were fed twice a day (at 0800 and 2000 h) with an experimental diet of high-producing dairy cows (53.55 g/DM day; Forage:Concentrate ratio, F:C of 40:60). Four levels of caffeine (0 ppm, 50 ppm, 100 ppm, and 150 ppm) were added to the diets as a treatment. The experiment was arranged in a randomized complete block design. Two blocks of four fermenters were run in two replicated periods of ten days. Statistical analyses were conducted in SAS version 9.4 for Windows (SAS Institute Inc., Cary, NC) using the GLIMMIX procedure. The addition of caffeine at a 50 ppm dose on continuous culture fermentation decreased the protozoal counts (Diplodinium spp.) (p = 0.03) and ammonia concentrations (p < 0.05). A treatment of 50 ppm of caffeine increased the DM, OM, and starch digestibility (p < 0.05). When caffeine doses increased further than 50 ppm, the OM, DM, and starch digestibility decreased linearly (p = 0.01). The total volatile fatty acids and fatty acid proportions were unaffected. However, the acetate-to-propionate ratio (A:P) tended to decrease linearly among treatments (p = 0.07). The means of pH measurements and maximum pH had a significantly linear decrease effect (p < 0.01). Caffeine may represent a potential rumen fermentation modifier for use in lactating cow diets.

Abstract Mo042: Poison Peptides May Contribute to Dysregulation of SERCA in Heart Failure

Proteolysis increases in heart disease, resulting in an accumulation of degraded membrane protein fragments in heart cells. Previous studies have shown that diverse hydrophobic alpha helices can bind and non-specifically inhibit the cardiac calcium pump SERCA. Thus, we hypothesized that partially degraded fragments of transmembrane proteins may directly inhibit SERCA or compete with native peptide regulators of the pump, like such as phospholamban. The resulting dysregulation of SERCA may contribute to calcium mishandling in heart failure. To test these hypotheses, purified cell membranes from non-failing or dilated cardiomyopathy human hearts were subjected to SDS-PAGE and mass spectrometry to identify protein fragments smaller than 26 kD. 1800 proteins were detected, of which 92 were upregulated >3 fold in the failing heart samples, consistent with increased production of small fragments from these membrane proteins. 9 of the upregulated fragments containing transmembrane segments were selected for further analysis based on sequence hydrophobicity and structural similarity to endogenous micropeptide regulators of SERCA. Of these 9 fragments, 6 showed ER localization, suggesting potential for a toxic interaction with SERCA. The relative binding of these candidates to SERCA was quantified with FRET microscopy. Fragments of three membrane proteins (SEC61B, VAMP3, VAMP8) showed an avid interaction with SERCA. To measure SERCA inhibition, we utilized a calcium activity assay was performed usingin which HEK293T cells were transfected with SERCA, ryanodine receptor, candidate peptides and rCepia as an ER calcium indicator. ER-calcium level was normalized to minimum fluorescence after caffeine addition and an ionomycin induced maximum fluorescence after addition of ionomycin and calcium and caffeine induced minimum. Unregulated Candidate poison peptides were compared to SERCA alone and SERCA-PLB phospholamban controls were also performed. . SEC61B demonstrated the a strongest inhibition, most (similar to phospholamban, ) while VAMP3 and VAMP8’s effect was more modest. This type of non-nativeThus, we propose accumulation of toxic transmembrane peptide fragments may inhibition could be contributinginhibit SERCA and contribute to the calcium mishandling seen in heart failure. Future experiments will be performed to quantify the relative abundance of the fragments compared to endogenous regulatory micropeptides.

An Improved Bulk DNA Extraction Method for Detection of Helicoverpa armigera (Lepidoptera: Noctuidae) Using Real-Time PCR.

Helicoverpa armigera is among the most problematic agricultural pests worldwide due to its polyphagy and ability to evolve pesticide resistance. Molecular detection methods for H. armigera have been developed to track its spread, as such methods allow for rapid and accurate differentiation from the native sibling species H. zea. Droplet digital PCR (ddPCR) is a preferred method for bulk screening due to its accuracy and tolerance to PCR inhibitors; however, real-time PCR is less expensive and more widely available in molecular labs. Improvements to DNA extraction yield, purity, and throughput are crucial for real-time PCR assay optimization. Bulk DNA extractions have recently been improved to where real-time PCR sensitivity can equal that of ddPCR, but these new methods require significant time and specialized equipment. In this study, we improve upon previously published bulk DNA extraction methods by reducing bench time and materials. Our results indicate that the addition of caffeine and RNase A improves DNA extraction, resulting in lower Cq values during real-time PCR while reducing the processing time and cost per specimen. Such improvements will enable the use of high throughput screening methods across multiple platforms to improve the probability of detection of H. armigera.

Beyond the buzz: the fatal consequences of caffeine overconsumption.

Caffeine is a naturally occurring stimulant present in dozens of plant species including Coffea arabica and Camellia sinensis, from which we obtain coffee and tea, respectively. It is one of the world's most widely consumed psychoactive substances frequently used to increase alertness, elevate mood, and ward off fatigue. In traditional preparations, caffeine is generally well-tolerated by the consumer. However, complications can arise with the addition of caffeine to products like energy drinks, medications, and supplements. Furthermore, with pure caffeine accessible online, a consumer may unknowingly or inadvertently consume caffeine in dangerous amounts. Symptoms of caffeine toxicity include classic central nervous system stimulation side effects, such as agitation, insomnia, gastrointestinal distress, tachycardia, seizures, and death in extreme cases. To evaluate concentrations of toxicological significance, caffeine cases were assessed at a large reference laboratory (NMS Labs). From 2019 to 2023, 406 blood cases underwent confirmation testing via LC-MS-MS; the mean and median caffeine concentrations were 35 and 4.8 µg/mL, respectively. While most caffeine-containing cases indicate traditional use in the general population with concentrations <25 µg/mL (62%, N = 254), 10% (N = 42) of the cases were >100 µg/mL, indicating levels which may contribute to a fatal outcome. To gain insight into the significance of caffeine in determining the cause and manner of death, cases with various manners of death are presented. Despite being one of the most common toxicological findings in medicolegal death investigations, caffeine is often overlooked. Screening results should undergo scrutiny, and confirmation testing should be considered in cases where caffeine intoxication is prominently featured in the case history or scene investigation.

Indigofera suffruticosa aerial parts extract induce G2/M arrest and ATR/CHK1 pathway in Jurkat cells

BackgroundIndigofera suffruticosa Mill. is used as a folk medicine for treating patients with leukemia, however very little is known regarding the molecular mechanism of its anti-leukemic activity and the chemical profile of the active extract. The present study aimed to reveal the molecular effect of I. suffruticosa aerial parts extract (ISAE) on leukemia cells and its chemical constituents.MethodsCytotoxicity of ISAE were determined by resazurin viability assay, multitox – Glo multiplex cytotoxicity assay, and Annexin V staining assay. Cell cycle profiles were revealed by propidium iodide staining assay. The effects of ISAE on G2/M arrest signaling and DNA damage were evaluated by Western blot assay and phospho-H2A.X staining assay. The chemical profile of ISAE were determined by tandem mass spectroscopy and molecular networking approach.ResultsWe showed that the acute lymphoblastic leukemia cell line Jurkat cell was more responsive to ISAE treatment than other leukemia cell lines. In contrast, ISAE did not induce cytotoxic effects in normal fibroblast cells. Cell cycle analysis revealed that ISAE triggered G2/M arrest in Jurkat cells in dose- and time-dependent manners. Elevation of annexin V-stained cells and caspase 3/7 activity suggested ISAE-induced apoptosis. Furthermore, ISAE alone could increase the phosphorylation of CDK1 at Y15 and activate the ATR/CHK1/Wee1/CDC25C signaling pathway. However, the addition of caffeine, a widely used ATR inhibitor to ISAE, reduced the phosphorylation of ATR, CHK1, and CDK1, as well as G2/M arrest in Jurkat cells. Moreover, increased phospho-H2A.X stained cells indicated the involvement of DNA damage in the anti-leukemic effect of ISAE. Finally, qualitative analysis using UPLC-tandem mass spectroscopy and molecular networking revealed that tryptanthrin was the most abundant organoheterocyclic metabolite in ISAE. At equivalent concentrations to ISAE, tryptanthrin induced G2/M arrest of Jurkat cells, which can be prevented by caffeine.ConclusionsISAE causes G2/M arrest via activating ATR/CHK1/CDK1 pathway and tryptanthrin is one of the active components of ISAE. Our findings provide subtle support to the traditional use of I. suffruitcosa in leukemia management in folk medicine.

Addition of dextrose and caffeine to the intravenous treatment of milk fever in Holstein Friesian cattle

A farmer reported a cow unable to stand 48 hours postpartum. The cow was a 2.5 years old dairy cow with a body weight of around 350 kg. The cow was fed elephant grass, standard concentrate (16–18%) crude protein, and drinking water ad libitum without mineral supplementation during the dry season. The cow's position and posture when lying down, ear temperature, and eye pupils were included in the physical examination. Availability of food and drink was examined to predict appetite and thirst. The results of the history and physical examination showed that the cow was unable to stand 48 hours after calving, had no appetite and eye reflexes, had cold ears, and trembling hind legs. The cow was laid on its right side, with its head turned to flank. Based on the anamnesis and physical examination, the cow was diagnosed as suffering from stage 2 puerperal hypocalcemia. The cow was infused via the jugular vein with a solution containing 270 mg calcium borogluconate, 70 mg magnesium borogluconate, 300 mg dextrose, 5 mg phosphorus element, 2 mg potassium chloride, and 5 mg caffeine per 1 mL of solution. Forty-five minutes after the infusion, the cow was able to stand, although it still looked weak. It could be concluded that the addition of dextrose and caffeine to the standard treatment of milk fever was beneficial for recovery.

Addition of dextrose and caffeine to the intravenous treatment of milk fever in Holstein Friesian cattle

A farmer reported a cow unable to stand 48 hours postpartum. The cow was a 2.5 years old dairy cow with a body weight of around 350 kg. The cow was fed elephant grass, standard concentrate (16–18%) crude protein, and drinking water ad libitum without mineral supplementation during the dry season. The cow's position and posture when lying down, ear temperature, and eye pupils were included in the physical examination. Availability of food and drink was examined to predict appetite and thirst. The results of the history and physical examination showed that the cow was unable to stand 48 hours after calving, had no appetite and eye reflexes, had cold ears, and trembling hind legs. The cow was laid on its right side, with its head turned to flank. Based on the anamnesis and physical examination, the cow was diagnosed as suffering from stage 2 puerperal hypocalcemia. The cow was infused via the jugular vein with a solution containing 270 mg calcium borogluconate, 70 mg magnesium borogluconate, 300 mg dextrose, 5 mg phosphorus element, 2 mg potassium chloride, and 5 mg caffeine per 1 mL of solution. Forty-five minutes after the infusion, the cow was able to stand, although it still looked weak. It could be concluded that the addition of dextrose and caffeine to the standard treatment of milk fever was beneficial for recovery.

Ecotoxicity of Caffeine as a Bio-Protective Component of Flax-Fiber-Reinforced Epoxy-Composite Building Material.

Caffeine is a verified bio-protective substance in the fight against the biodegradation of cellulose materials, but its ecotoxicity in this context has not yet been studied. For this reason, the ecotoxicity of flax-fiber-reinforced epoxy composite with or without caffeine was tested in the present study. Prepared samples of the composite material were tested on freshwater green algal species (Hematococcus pluvialis), yeasts (Saccharomyces cerevisae), and crustacean species (Daphnia magna). Aqueous eluates were prepared from the studied material (with caffeine addition (12%) and without caffeine and pure flax fibers), which were subjected to chemical analysis for the residues of caffeine or metals. The results indicate the presence of caffeine up to 0.001 mg/L. The eluate of the studied material was fully toxic for daphnids and partially for algae and yeasts, but the presence of caffeine did not increase its toxicity statistically significantly, in all cases. The final negative biological effects were probably caused by the mix of heavy metal residues and organic substances based on epoxy resins released directly from the tested composite material.

Continuous removal of caffeine in a horizontal-flow anaerobic immobilized biomass bioreactor: identification of transformation products.

Anaerobic bioreactors are an efficient technology for the biodegradation of emerging contaminants in environmental matrices. In this work, a horizontal-flow anaerobic immobilized biomass (HAIB) bioreactor was used to remove caffeine (CAF), which is frequently found in various aqueous matrices. The acrylic bench top bioreactor, with dimensions of 100 × 5.00cm, was operated with a hydraulic retention time (HRT) of 12h, during 45weeks, under mesophilic conditions. The operation was performed in 4 phases: without CAF addition (phase I); CAF spiked at 300μg L-1 (phase II); CAF at 600μg L-1 (phase III); and CAF at 900μg L-1 (phase IV). Samples of bioreactor influent and effluent were analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The bioreactor removed organic matter (OM) and CAF with efficiencies of 88 and 93%, respectively. The first-order apparent removal constant (Kapp) values for OM and CAF were 0.419 and 0.304h-1, respectively. Five transformation products (TPs) were identified, with m/z 243, 227, 211, and 181 (two products). The HAIB bioreactor is a suitable system for the removal of CAF present in wastewater, even at a concentration level of µg L-1.

Differential consumption of alcohol, caffeine, and caffeinated alcohol by adolescent rats, and effects on post-adolescent gene expression signatures in the nucleus accumbens and orbitofrontal cortex

Caffeinated alcoholic beverages (CABs) are widely consumed despite little known about their behavioral and biological effects. Furthermore, CABs are also popular among adolescents, a particularly vulnerable and maturing demographic. In this preliminary study, we compared levels of daily adolescent voluntary consumption of caffeine (0.03%), alcohol (10%), caffeinated alcohol (0.03% + 10%), or vehicle and evaluated the effects of this on mRNA expression in brain regions associated with addiction and known to be affected by each drug. Beginning on postnatal day 30, rats were allowed unrestricted access to gelatin combined with one, both, or neither drug for twenty days. Compared to vehicle-consuming animals, consumption of gelatin was significantly attenuated when alcohol was included. The addition of caffeine to alcohol increased alcohol consumption in the early days of access compared to alcohol alone; however, after two weeks, alcohol consumption between these groups reached comparable levels. Compared to animals consuming caffeine alone, combining caffeine with alcohol significantly reduced caffeine intake. Targeted mRNA analysis of tissue collected from the nucleus accumbens and orbitofrontal cortex after the consumption period identified unique patterns of differentially expressed genes between treatment groups, across a broad array of neurotransmitter systems. Of particular note were genes related to a number of solute transporters and serotonergic functions. This preliminary work suggests unique pharmacological and behavioral effects from consuming caffeinated alcohol during adolescence. Since CABs are widely consumed by adolescents, these results suggest that more research into the pharmacological and behavioral effects elicited by CABs is warranted.

Characteristics of Chitosan Films with the Bioactive Substances-Caffeine and Propolis.

Chitosan is a natural and biodegradable polymer with promising potential for biomedical applications. This study concerns the production of chitosan-based materials for future use in the medical industry. Bioactive substances-caffeine and ethanolic propolis extract (EEP)-were incorporated into a chitosan matrix to increase the bioactivity of the obtained films and improve their mechanical properties. Acetic and citric acids were used as solvents in the production of the chitosan-based films. The obtained materials were characterized in terms of their antibacterial and antifungal activities, as well as their mechanical properties, including tensile strength and elongation at break. Moreover, the chemical structures and surface morphologies of the films were assessed. The results showed that the solution consisting of chitosan, citric acid, caffeine, and EEP exhibited an excellent antiradical effect. The activity of this solution (99.13%) was comparable to that of the standard antioxidant Trolox (92.82%). In addition, the film obtained from this solution showed good antibacterial activity, mainly against Escherichia coli and Enterococcus faecalis. The results also revealed that the films produced with citric acid exhibited higher activity levels against pathogenic bacteria than the films obtained with acetic acid. The antimicrobial effect of the chitosan-based films could be further enhanced by adding bioactive additives such as caffeine and propolis extract. The mechanical tests showed that the solvents and additives used affected the mechanical properties of the films obtained. The film produced from chitosan and acetic acid was characterized by the highest tensile strength value (46.95 MPa) while the chitosan-based film with citric acid showed the lowest value (2.28 MPa). The addition of caffeine and propolis to the film based on chitosan with acetic acid decreased its tensile strength while in the case of the chitosan-based film with citric acid, an increase in strength was observed. The obtained results suggested that chitosan films with natural bioactive substances can be a promising alternative to the traditional materials used in the medical industry, for example, as including biodegradable wound dressings or probiotic encapsulation materials.

SECM investigation on pH changes in cellular environment induced by caffeine

This work shows the results of the fabrication and application of a potentiometric microsensor for real-time pH monitoring in the vicinity of C2C12 cell line muscle cells using Scanning Electrochemical Microscopy (SECM). This was achieved by electrodeposition of an iridium oxide film onto the surface of a dual sensor containing two microelectrodes (Au and Pt). The Au microelectrode was coated with an iridium oxide film and used as a potentiometric pH sensor. The sensor exhibited a super Nernstian response (around 70 mV pH−1), and its precise positioning above a single C2C12 cell was accomplished by means of an approach curve recorded with the Pt microelectrode. pH changes were induced by changing the cellular metabolism through the addition of caffeine to the culture medium, and an average decrease of up to 0.5 units in pH was noticed by measuring the pH at 10 µm from the cell surface. Much smaller pH changes were observed in control experiments, confirming that caffeine induces acidosis and that such a phenomenon can be monitored using the fabricated dual sensor coupled to SECM.

Effect of Melatonin and Caffeine Supplementation to Freezing Medium on Cryosurvival of Peruvian Paso Horse Sperm Using a Two-Step Accelerating Cooling Rate.

This research examined the antioxidant and cryoprotective effects of melatonin (ME) and caffeine (CAF) supplementation in freezing medium on the cryosurvival of Peruvian Paso horse sperm using a two-step accelerating cooling rate. Twenty ejaculates from four adult and fertile stallions were recovered, initially diluted with INRA-96®, and finally frozen with INRA-Freeze® with either no supplementation (as control), 1 μM ME, or 2 mM CAF using a two-ramp freezing system content inside a cryogenic-box and liquid nitrogen vapors. The sperm kinematic parameters and integrity of the plasma and acrosomal membranes of fresh semen and cryopreserved samples were evaluated using the CASA system (SCA-Evolution® 2018) and PI/fluorescein isothiocyanate-conjugated peanut (Arachis hypogaea) agglutinin double fluorescent test, respectively. The oxidative stress of post-thaw sperm samples was also assessed using the CellRox Deep Red fluorescence test. The results showed that curvilinear velocity and average-path velocity were greater (p < 0.05) after freezing with CAF than the control group. In addition, there were significance differences (p < 0.01) between stallions (1-4) in post-thaw kinematic parameters regardless of ME or CAF addition. Both ME and CAF improved (p < 0.05) the proportion of sperm with intact plasma membranes and intact acrosomes. Nevertheless, neither CAF nor ME improved the oxidative stress after the cryopreservation process.

Matrix-Specific Effects on Caffeine and Chlorogenic Acid Complexation in a Novel Extract of Whole Coffea arabica Coffee Cherry by NMR Spectroscopy.

Coffee cherry is a rich source of caffeine and chlorogenic acids. In this study we investigate the structural analysis of caffeine-enriched whole coffee cherry extracts, CEWCCE by using 1H and 13C NMR spectroscopy. The changes in 1H chemical shift data in NMR spectra of CEWCCE compared to pure caffeine indicated the formation of complexes between caffeine and chlorogenic acids in aqueous solution. The effect of complexation on the peak position of caffeoylquinic acid and caffeine resonance with increasing addition of caffeine was investigated. 2D NOESY experiments show the presence of cross-peaks that are due to the proximity of chlorogenic acid and caffeine molecules in stable complexes in protic solvents. The quantification data of caffeine by 1H qNMR was found to be in close agreement with the data obtained by HPLC analysis.

Abstract 15591: Acute Dantrolene Treatment Reverses Arrhythmogenic Substrate and Reduces Triggers Induced by Ryanodine Receptor 2 Hyperactivity in Human Hearts

Introduction: Ryanodine receptor 2 (RyR2) hyperactivity is commonly observed in structural heart diseases that are a result of ischemia or heart failure. It results in abnormal calcium handling and calcium leak that can trigger arrhythmias. Dantrolene, a RyR inhibitor, is used to prevent calcium leak from RyR1 in skeletal muscles. Hypothesis: Suppressing RyR2 hyperactivity with acute dantrolene treatment can reduce arrhythmia burden in human hearts. Methods: Human donor hearts that were not used in transplantation were obtained and 1 cm 3 cubes were isolated from the left ventricle. Slices at 400 μm thickness were generated from these cubes, pinned and perfused with Tyrode’s solution in a recording tissue chamber. Pseudo-ECGs were recorded with ECG electrodes and the slices were optically mapped to measure conduction velocity (CV), action potential duration (APD) and calcium transient duration (CaTD). After an initial 30 min equilibration period, baseline optical recordings were obtained. Slices were then treated with 1) Isoproterenol (Iso, 250 nM) to stimulate β-adrenergic receptors, 2) Caffeine (200 μM) for RyR2 receptor activation and 3) Dantrolene (10 μM), sequentially. Dual optical recordings, Vm and Ca, were obtained after each treatment. Results: Substrate: Iso reduced APD (425±36 vs 394±43, p=0.03), as expected, and addition of Caffeine restored APD to baseline. More importantly, addition of Dantrolene prolonged APD even further (460±90, p=0.04). CaTD was also similarly reduced by Iso (445±48 vs 387±25, p=0.04) and restored to baseline by Caffeine+Iso. No significant changes in CV were measured under any condition. Trigger: In slices where PVCs were inducible, Caffeine+Iso increased occurrence of PVCs (20 vs 53 PVCs/min) while addition of Dantrolene reduced PVC incidence (18 PVCs/min). Conclusions: Dantrolene treatment, acutely reversed proarrhythmogenic substrate and reduced triggers and could therefore be a suitable approach for anti-arrhythmic therapy in patients with structural heart disease. Additionally, human LV slice preparation is useful in antiarrhythmic drug studies.

Resistance Exercise Alone Or In Conjunction With Caffeine On Measures Of Left Ventricular Workload In Women

Resistance exercise alone or in conjunction with caffeine increases heart rate and blood pressure in resistance-trained women. While acute resistance exercise has been shown to increase measures of left ventricular workload, the addition of caffeine on these responses is unknown. PURPOSE: To evaluate alterations in left ventricular workload at rest, following acute caffeine supplementation or placebo, as well as during recovery from a fatiguing bout of resistance exercise in resistance-trained women. METHODS: Eleven resistance-trained women (Mean ± SD: Age: 24 ± 4 yrs) participated in a counterbalanced, double blind, placebo-controlled, crossover-design study. Each participant drank 4 mg/kg of caffeine mixed with water. Applanation tonometry was used to measure left ventricular workload at rest (Rest1), 45 minutes after caffeine ingestion (Rest2), immediately post-resistance exercise (Post 1), and 10 minutes post-resistance exercise (Post2). The acute bout of resistance exercise consisted of two sets at 75% 1-repetition maximum (1RM) for 10 repetitions, and one set at 70%1RM with repetitions to failure on the squat and bench press. Two minutes of rest were given between sets and exercises. A 2x4 two-way analysis of variance (ANOVA) was used to assess the effects of condition with a repeated measure of time. RESULTS: There were significant main effects of time for wasted left ventricular energy (Rest1: 608 ± 687dynes*s/cm2; Rest2: 529 ± 667dynes*s/cm2; Post1: 2154 ± 1164dynes*s/cm2; Post2: 1956 ± 1873dynes*s/cm2, p = 0.003), systolic pressure time index (Rest1: 1900 ± 290 mmHg*s; Rest2: 1937 ± 390 mmHg*s; Post1: 2769 ± 535 mmHg*s; Post2: 2652 ± 512 mmHg*s, p = 0.001), diastolic pressure time index (Rest1: 2827 ± 244 mmHg*s; Rest2: 2973 ± 294 mmHg*s; Post1: 2349 ± 319 mmHg*s; Post2: 2289 ± 402 mmHg*s, p = 0.001), and the subendocardial viability ratio (Rest1: 154 ± 34%; Rest2: 163 ± 44%; Post1: 90 ± 31%; Post2: 92 ± 33%, p = 0.001). While there were no significant differences from Rest1 to Rest2, there were significant increases for each of these variables such that Post1 and Post2 were augmented above Rest1 and Rest2. CONCLUSION: These data suggest that resistance exercise in conjunction with 4 mg/kg of caffeine does not mediate additional left ventricular workload compared to a placebo in resistance-trained women.

Intermolecular Copigmentation of Malvidin-3-O-glucoside with Caffeine in Water: The Effect of the Copigment on the pH-Dependent Reversible and Irreversible Processes.

Intermolecular copigmentation of malvidin-3-O-glucoside with caffeine was studied using a holistic procedure that includes the extension to basic pH values. In moderately basic solutions (7.5 < pH < 9.5) and independently of the copigment presence, there is a pH region where degradation of the quinoidal base and anionic quinoidal bases is faster than hydration and OH– nucleophilic addition, preventing the system from reaching the equilibrium. Intermolecular copigmentation with caffeine reduces significantly the degradation rate of quinoidal bases. In a more basic medium, the equilibrium is reached and degradation occurs from the anionic chalcones. In this case, the addition of caffeine also reduces the degradation rate in the interval 10 < pH < 11.5.

Central nervous system stimulants promote nerve cell death under continuous hypoxia

Intake of central nervous system (CNS) stimulants causes hypoxia and brain edema, which results in nerve cell death. However, no study has yet investigated the direct and continuous effects on nerve cells of CNS stimulants under hypoxia. Thus, based on autopsy cases, the effects of CNS stimulant drugs on the CNS were examined. The pathological changes in cultured nerve cells when various CNS stimulants were added under a hypoxic condition were also investigated. Five groups (Group A, stimulants; Group B, stimulants with psychiatric drugs; Group C, caffeine; Group D, psychiatric drugs; and Group E, no drugs) according to the detected drugs in autopsy cases were compared, and brain edema was evaluated using morphological findings. Furthermore, the number of dead cultured nerve cells was counted after the addition of drugs (4-aminopyridine (4-AP), caffeine, and ephedrine) under hypoxia (3% O2). Staining with anti-receptor-interacting protein 3 (RIP3) and other associated stains was also performed to investigate the neuronal changes in the brain. Group A showed significantly more brain edema than the other groups. In the culture experiments, the ratio of nerve cell death after the addition of 4-AP was the highest in the hypoxic condition. Groups with stimulants detected were stained more strongly by RIP3 immunostaining than by other staining. Addition of stimulants to cultured nerve cells in a persistent hypoxic condition led to severe cytotoxicity and nerve cell death. These findings suggest that necroptosis is involved in nerve cell death due to the addition of CNS stimulants in the hypoxic condition.

Hydrophilic drug release from electrospun membranes made out of thermo and pH-sensitive polymers

Electrospun fibers of the thermo-and pH sensitive poly(N-vinylcaprolactam-co-acrylic acid) (Poly(NVCL-co-AA) loaded with 10% and 30 wt% caffeine (Caf) were obtained by electrospinning and evaluated as potential drug delivery systems. Caffeine was used as a hydrophilic drug model, and poly(NVCL-co-AA) containing either 20 or 30 mol% AA was used as a carrier. The fibers morphology, as well as, their interaction with caffeine, were studied using different analytical techniques. The cytotoxicity of the different obtained fibers was evaluated by cell viability assays using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and mouse embryonic fibroblasts cell line (MEF cells). Caffeine release was studied at temperatures of 25 °C and 42 °C and pH of 1.2 and 7.4. Beadless copolymer fibers with diameters ranging from 1 μm to 2 μm were obtained. The addition of caffeine, which was in crystalline form after being encapsulated in the fibers, resulted in an increase of fiber diameter. The obtained membranes were found to be not cytotoxic. The entrapment of caffeine was greater for the copolymer containing 30 mol% AA due to a greater affinity of AA to caffeine. At a pH of 1.2 and at both temperatures of 25 °C and 42 °C, as well as, at a pH of 7.4 and a temperature of 42 °C, a Fickian diffusion mechanism for all copolymer fiber mats was observed. At a pH of 7.4 and 25 °C the release profile showed a high rate and followed a zero-order model, due to the fast dissolution of caffeine in water. These results indicated that thermo-and pH-sensitive poly(NVCL-co-AA) are promising candidates for controlled release of hydrophilic drugs.

Caffeine and canopy cover interact to alter biofilm nutrient content, benthic invertebrates, and insect emergence

AbstractThe addition of trace contaminants to surface waters is recognized as a rising environmental concern and caffeine is among those most commonly detected. Classic toxicological analyses of single organisms have described some of the impacts of caffeine on freshwater organisms, but few have examined ecological interactions, food webs, or aquatic‐terrestrial linkages, especially in natural aquatic systems. This study used an in situ manipulative experiment to effects of caffeine addition on aquatic biofilms and biomass of aquatic and emergent insects. We used chemical diffusing substrata to introduce small concentrations of caffeine to streams and analyzed effects on downstream biofilm nutrient content, benthic macroinvertebrates, and emergent insects. We found that caffeine addition decreased the biomass of emergent insects by 56% and altered biofilm nutrient content in complex ways that interact with canopy cover, with stronger effects of caffeine addition under low canopy cover (higher light). Thus, the impacts of this common aquatic contaminant may influence the linked riparian food web by decreasing emergent insects, an important food source for riparian insectivores.