Hepatoprotective Effect of Cymbopogon Citratus Aqueous Extract Against Hydrogen Peroxide-Induced Liver Injury in Male Rats

Background

Cymbopogon citratus (Poaceae) a tropical perennial herb plant that is widely cultivated to be eaten either fresh with food or dried in tea or soft drink has been reported to possess a number of medicinal and aromatic properties. This study aimed at evaluating the protective effects of C. citratus aqueous extract against liver injury induced by hydrogen peroxide (H₂O₂), in male rats.

Materials and Methods

Twenty-five rats were randomly divided into five different groups of five animals in each group; (1) Control. (2) Received H₂O₂ (0.5%) with drinking water. (3), and (4) received H₂O₂ and C. citratus (100 mg·kg⁻¹ b wt), vitamin C (250 mg·kg⁻¹ b wt) respectively. (5), was given C. citratus alone. The treatments were administered for 30 days. Blood samples were collected and serum was used for biochemical assay including liver enzymes activities, total protein, total bilirubin and malonaldehyde, glutathione in serum and liver homogenates. Liver was excised and routinely processed for histological examinations.

Results

C. citratus attenuated liver damage due to H₂O₂ administration as indicated by the significant reduction (p<0.05), in the elevated levels of ALT, AST, ALP, LDH, TB, and MDA in serum and liver homogenates; increase in TP and GSH levels in serum and liver homogenates; and improvement of liver histo-pathological changes. These effects of the extract were similar to that of vitamin C which used as antioxidant reference.

Conclusion

C. citratus could effectively ameliorate H₂O₂-induced oxidative stress and prevent liver injury in male rats.     

Gastric emptying after pickle-juice ingestion in rested, euhydrated humans

Context:

Small volumes of pickle juice (PJ) relieve muscle cramps within 85 seconds of ingestion without significantly affecting plasma variables. This effect may be neurologic rather than metabolic. Understanding PJ''s gastric emptying would help to strengthen this theory.

Objective:

To compare gastric emptying and plasma variables after PJ and deionized water (DIW) ingestion.

Design:

Crossover study.

Setting:

Laboratory.

Patients or Other Participants:

Ten men (age  =  25.4 ± 0.7 years, height  =  177.1 ± 1.6 cm, mass  =  78.1 ± 3.6 kg).

Intervention(s):

Rested, euhydrated, and eunatremic participants ingested 7 mL·kg⁻¹ body mass of PJ or DIW on separate days.

Main Outcome Measure(s):

Gastric volume was measured at 0, 5, 10, 20, and 30 minutes postingestion (using the phenol red dilution technique). Percentage changes in plasma volume and plasma sodium concentration were measured preingestion (−45 minutes) and at 5, 10, 20, and 30 minutes postingestion.

Results:

Initial gastric volume was 624.5 ± 27.4 mL for PJ and 659.5 ± 43.8 mL for DIW (P > .05). Both fluids began to empty within the first 5 minutes (volume emptied: PJ  =  219.2 ± 39.1 mL, DIW  =  305.0 ± 40.5 mL, P < .05). Participants who ingested PJ did not empty further after the first 5 minutes (P > .05), whereas in those who ingested DIW, gastric volume decreased to 111.6 ± 39.9 mL by 30 minutes (P < .05). The DIW group emptied faster than the PJ group between 20 and 30 minutes postingestion (P < .05). Within 5 minutes of PJ ingestion, plasma volume decreased 4.8% ± 1.6%, whereas plasma sodium concentration increased 1.6 ± 0.5 mmol·L⁻¹ (P < .05). Similar changes occurred after DIW ingestion. Calculated plasma sodium content was unchanged for both fluids (P > .05).

Conclusions:

The initial decrease in gastric volume with both fluids is likely attributable to gastric distension. Failure of the PJ group to empty afterward is likely due to PJ''s osmolality and acidity. Cardiovascular reflexes resulting from gastric distension are likely responsible for the plasma volume shift and rise in plasma sodium concentration despite nonsignificant changes in plasma sodium content. These data support our theory that PJ does not relieve cramps via a metabolic mechanism.     

Evaluation of the effects of ozone therapy in the treatment of intra-abdominal infection in rats

INTRODUCTION

The antibacterial effect of ozone (O₃) has been described in the extant literature, but the role of O₃ therapy in the treatment of certain types of infection remains controversial.

OBJECTIVES

To evaluate the effect of intraperitoneal (i.p.) O₃ application in a cecal ligation/puncture rat model on interleukins (IL-6, IL-10) and cytokine-induced neutrophil chemoattractant (CINC)-1 serum levels, acute lung injury and survival rates.

METHODS

Four animal groups were used for the study: a) the SHAM group underwent laparotomy; b) the cecal ligation/puncture group underwent cecal ligation/puncture procedures; and c) the CLP+O₂ and CLP+O₃ groups underwent CLP+ corresponding gas mixture infusions (i.p.) throughout the observation period. IL-6, CINC-1 and IL-10 concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Acute lung injury was evaluated with the Evans blue dye lung leakage method and by lung histology. P<0.05 was considered significant.

RESULTS

CINC-1 was at the lowest level in the SHAM group and was lower for the CLP+O₃ group vs. the CLP+O₂ group and the cecal ligation/puncture group. IL-10 was lower for the SHAM group vs. the other three groups, which were similar compared to each other. IL-6 was lower for the SHAM group vs. all other groups, was lower for the CLP+O₃ or CLP+O₂ group vs. the cecal ligation/puncture group, and was similar for the CLP+O₃ group vs. the CLP+O₂ group. The lung histology score was lower for the SHAM group vs. the other groups. The Evans blue dye result was lower for the CLP+O₃ group vs. the CLP+O₂ group and the cecal ligation/puncture group but similar to that of the SHAM group. The survival rate for the CLP+O₃ group was lower than for the SHAM group and similar to that for the other 2 groups (CLP and CLP+O₂).

CONCLUSION

Ozone therapy modulated the inflammatory response and acute lung injury in the cecal ligation/puncture infection model in rats, although there was no improvement on survival rates.     

Evaluation of the Antioxidant Activity of Root Extract of Pepper Fruit (Dennetia Tripetala), and It's Potential for the Inhibition of Lipid Peroxidation

Background

The antioxidant properties of ethanolic root extract of pepper fruit (Donnetia tripetala), and its effect on lipid peroxidation of some fresh beef tissues during frozen storage were investigated.

Materials and Methods

The antioxidant parameters were assessed using standard methods, while malondialdehyde levels of different fresh beef tissue sections treated with the extract prior to freezing, were estimated in a colorimetric reaction with thiobarbituric acid.

Results

The H₂O₂-scavenging ability of the extract was similar to that of ascorbic acid, with a maximum scavenging power of 55.61 ±4.98%, and an IC₅₀ value of 86µg/ml. The extract exhibited a concentration-dependent ferric ion-reducing power, although this was significantly lower relative to that of the ascorbic acid (p < 0.05). The total phenolic content was 212.5 ± 0.002 mg/g, while the nitric oxide-scavenging ability was 64.33 ± 0.2% after 150 min. The capacity of the extract to inhibit lipid peroxidation in frozen heart muscle slices was significantly higher than that of vitamin C (p < 0 .05), but comparable to vitamins C and E in frozen testes and kidney slices.

Conclusion

These results suggest that the root extract of D. tripetala is rich in antioxidants which can be applied to meat preservation during refrigerated storage.     

Motor-neuron pool excitability of the lower leg muscles after acute lateral ankle sprain

Context:

Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown.

Objective:

To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls.

Design:

Case-control study.

Setting:

Laboratory.

Patients or Other Participants:

Ten individuals with acute ankle sprains (6 females, 4 males; age = 19.2 ± 3.8 years, height = 169.4 ± 8.5 cm, mass = 66.3 ±11.6 kg) and 10 healthy individuals (6 females, 4 males; age = 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass = 66.3 ± 10.2 kg) participated.

Intervention(s):

The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs.

Main Outcome Measure(s):

The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (H_max) and maximal muscle response (M_max) and was then normalized using the H_max:M_max ratio.

Results:

The soleus MNPE in the ankle-sprain group was higher in the injured limb (H_max:M_max = 0.63; 95% confidence interval [CI], 0.46, 0.80) than in the uninjured limb (H_max:M_max = 0.47; 95% CI, 0.08, 0.93) (t₆ = 3.62, P = .01). In the acute ankle-sprain group, tibialis anterior MNPE tended to be lower in the injured ankle (H_max:M_max = 0.06; 95% CI, 0.01, 0.10) than in the uninjured ankle (H_max:M_max = 0.22; 95% CI, 0.09, 0.35), but this finding was not different (t₉ = −2.01, P = .07). No differences were detected between injured (0.22; 95% CI, 0.14, 0.29) and uninjured (0.25; 95% CI, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t₉ = −0.739, P = .48). We found no side-to-side differences in any muscle among the healthy group.

Conclusions:

Facilitated MNPE was present in the involved soleus muscle of patients with acute ankle sprains, but no differences were found in the fibularis longus or tibialis anterior muscles.     

Vitamin C modulates DNA damage induced by hydrogen peroxide in human colorectal adenocarcinoma cell lines (HT29) estimated by comet assay in vitro

Introduction

Cancer cells, compared to normal cells, are under increased oxidative stress associated with oncogenic transformation, alterations in metabolic activity, and increased generation of reactive oxygen species.

Material and methods

We investigated the ability of vitamin C to reduce the damage induced by hydrogen peroxide, in human colorectal adenocarcinoma cells in vitro by the comet assay. Additionally, we measured the kinetics and efficacy of the repair of DNA damage after incubation with vitamin C in the presence of H₂O₂.

Results

The obtained results showed that 1 h pre-incubation with vitamin C and exposure to H₂O₂ for the last 10 min of incubation caused a statistically significant (p < 0.05) increase in DNA migration in comet tails in all experimental series. For the 10 µM, 25 µM, 50 µM, 100 µM vitamin C concentrations the levels of DNA damage were as follows: 18.6%, 21.1%, 25.3% and 27.2%, respectively, as compared to the untreated cells (3.26%). However, in comparison with H₂O₂ alone (29.1%), we observed a statistically significant (p < 0.05) decrease of the genotoxic effect in HT29 cells induced by H₂O₂ for the two lowest of concentrations of vitamin C: 10 µM and 25 µM. The HT29 cells were able to achieve effective repair of the damaged DNA within 60 and 120 min after incubation with the tested compounds. All the values obtained in the test were statistically significant (p < 0.05).

Conclusions

Vitamin C caused a weaker DNA damaging effect of hydrogen peroxide and positively influences the level of oxidative DNA damage in HT29 cells (decrease ∼ 30%). We noted that DNA damage was effectively repaired during 120 min postincubation in the tested cells and that oxidative damage was the major type of damage.     

Effect of vitamin E in nonalcoholic fatty liver disease with metabolic syndrome: A propensity score-matched cohort study

Background/Aims

Vitamin E improves the biochemical profiles and liver histology in nonalcoholic steatohepatitis, but the role of vitamin E is not clearly defined in the management of nonalcoholic fatty liver disease (NAFLD) which includes both simple steatosis and steatohepatitis. Co-morbid metabolic syndrome increases the probability of steatohepatitis in NAFLD. In this study, we aimed to determine the short-term effects of vitamin E and off-treatment durability of response in a propensity-score matched cohort of NAFLD patients with metabolic syndrome.

Methods

A retrospective cohort was constructed by retrieving 526 consecutive NAFLD patients from the electronic medical record data warehouse of a tertiary referral hospital in South Korea. Among them, 335 patients (63.7%) had metabolic syndrome and were eligible for vitamin E therapy. In order to assess the effect of vitamin E, propensity score matching was used by matching covariates between control patients (n=250) and patients who received vitamin E (n=85).

Results

The PS-matched vitamin E group (n=58) and control group (n=58) exhibited similar baseline metabolic profiles. After 6 months of vitamin E therapy, the mean ALT levels decreased significantly compared to PS-matched control (P<0.01). The changes in metabolic profiles (body weight, lipid and glucose levels) did not differ between control and vitamin E groups during the study period.

Conclusions

Short-term vitamin E treatment significantly reduces ALT levels in NAFLD patients with metabolic syndrome, but metabolic profiles are not affected by vitamin E.     

The Relationship between Gastric Juice Nitrate/Nitrite Concentrations and Gastric Mucosal Surface pH

Purpose

To investigate gastric juice nitrate/nitrite concentration according to mucosal surface pH extent (area) of gastric corpus intimately contacting the gastric juice.

Materials and Methods

We included ninety-nine patients with dyspepsia. To evaluate gastric mucosal surface pH and its extent, gastric chromosocpy was performed by spraying phenol red dye on the corpus mucosa and estimating the extent of area with color changed. Nitrate/nitrite concentrations and pH of gastric juice were measured by ELISA and pH meter, respectively. Silver staining was done to histologically confirm the presence of Helicobacter pylori.

Results

Intragastric nitrate/nitrite concentrations in patients, showing phenol red staining mucosa were higher than those of unstaining mucosa (p=0.001): the more extensive in the area of phenol red staining area of corpus, the higher gastric juice pH found (r=0.692, p<0.001). Furthermore, the intragastric nitrate/nitrite concentrations correlated positively with gastric juice pH (r=0.481, p<0.001).

Conclusion

The changes of mucosal surface pH and its extent in gastric corpus might affect either pH or nitrate/nitrite level of gastric juice.     

Efficacy of vitamin E and selenium for the prevention of intra-abdominal adhesions in rats: uterine horn models

OBJECTIVE:

This study compares the efficacies of vitamin E and selenium, both individually and in combination, for the prevention of postoperative intra-abdominal adhesions in rats.

METHODS:

Forty-seven female rats were divided into five groups. The sham animals (S group, n = 7) were given only laparotomies and intraperitoneally received 0.9% NaCl (2 ml). In the 40 other rats, abrasions of the left uterine horn were performed, followed by intraperitoneal administration of either 2 ml 0.9% NaCl (C group), 10 mg vitamin E (vitamin E group), 0.2 mg/kg selenium (Se group) or 10 mg vitamin E with 0.2 mg/kg selenium (vitamin E + Se group), with 10 animals in each treatment group.

RESULTS:

Adhesion formation was significantly reduced in animals in the Se and vitamin E + Se groups (p<0.05). Tissue catalase and glutathione peroxidase activities did not significantly differ between the groups. However, catalase and glutathione peroxidase activities and reduced glutathione levels were slightly increased in the vitamin E, Se and vitamin E + Se groups. In the vitamin E group, malondialdehyde concentrations were significantly lower than in the C group (p<0.05), but no significant differences were present among the S, C, Se and vitamin E + Se groups. Levels of nitric oxide were significantly higher in the C group than in the other groups (p<0.01).

CONCLUSION:

Intraperitoneal administration of selenium or combined vitamin E and selenium appears to be effective in preventing intra-abdominal adhesion formation in rat models through the reduction of lipid peroxidation products.     

Acute effect of phosphodiesterase type 5 inhibitor on serum oxidative status and prolidase activities in men with erectile dysfunction

OBJECTIVES:

To investigate the acute effect of phosphodiesterase type 5 (PDE5) inhibitor on erectile dysfunction by evaluating serum oxidative status and prolidase activity.

METHODS:

Serum samples of 36 patients with erectile dysfunction and 30 control cases were analyzed for total antioxidant status, total oxidant status, and prolidase activity, before and after the administration of tadalafil citrate.

RESULTS:

Before and after tadalafil citrate administration, serum total antioxidant status, total oxidant status, and prolidase were 1.1±0.0 vs. 1.6±0.0 µmol H₂O₂ Eq/L, 10.3±1.1 vs. 6.9±1.2 µmol H₂O₂ Eq/L, and 236.4±19.5 vs. 228.2±19.2 U/L, respectively (p<0.0001 for all).

CONCLUSIONS:

Evaluation of serum oxidative status and prolidase activity confirmed the beneficial acute effects of PDE5 inhibitor in patients with erectile dysfunction.     

Vitamin D Levels in Children and Adolescents with Antiepileptic Drug Treatment

Purpose

This study was to evaluate the relationship of 25(OH)D₃ levels with anticonvulsant use and other possible factors in epileptic children and adolescents.

Materials and Methods

We studied 143 patients with epilepsy (90 boys, 53 girls; 11.21±4.49 years), who had been treated with anticonvulsants for more than 1 year. Patients who had taken multiple vitamins before the blood test and those who have the limitation of physical activity (wheelchair-bound) were excluded from the study. We evaluated the difference in vitamin D status according to the type and number of anticonvulsants taken and other factors such as gender, age, intelligence and seizure variables.

Results

For patients with mental retardation or developmental delay, 25(OH)D₃ levels were lower than the levels in patients with normal intelligence quotient levels (p=0.03). 25(OH)D₃ levels were lower in patients who had taken anticonvulsants for more than 2 years as compared to those who had taken them for less than 2 years (p=0.03). Those taking oxcarbazepine had significantly lower vitamin D levels than patients taking valproic acid (p=0.01). However, no effects of number of anticonvulsants taken were detectable. More than two-thirds of the patients were diagnosed with osteopenia or osteoporosis in patients showing either vitamin D insufficiency or deficiency.

Conclusion

The possibility of vitamin D deficiency can be considered in pediatric patients taking anticonvulsants if they have mental retardation or developmental delay or if they have been taking anticonvulsants for more than 2 years or taking hepatic enzyme inducing drugs.     

The role of oxidative stress and antioxidants in the pathogenesis of age-related macular degeneration

OBJECTIVE:

To investigate the role of oxidant/antioxidant status and protein oxidation in the development of age-related macular degeneration.

METHOD:

The activities of serum superoxide dismutase and glutathione peroxidase and the levels of serum malondialdehyde, advanced oxidation protein products, glutathione and vitamin C were measured in 25 patients with age-related macular degeneration and 25 control subjects without age-related macular degeneration.

RESULT:

The malondialdehyde and advanced oxidation protein product levels in the serum were significantly higher in the age-related macular degeneration patient group than in the control group (p<0.05). The superoxide dismutase activity in the serum was significantly lower in the age-related macular degeneration patient group than in the control group (p<0.05). The levels of vitamin C and glutathione and the activity of glutathione peroxidase in the serum were unchanged between groups (p>0.05).

CONCLUSION:

The results of the present study suggest that decreased effectiveness of the antioxidant defense system and increased oxidative stress may play a role in the pathogenesis of age-related macular degeneration.     

Piper Sarmentosum Increases Nitric Oxide Production in Oxidative Stress: A Study on Human Umbilical Vein Endothelial Cells

OBJECTIVE:

Nitric oxide produced by endothelial nitric oxide synthase (eNOS) possesses multiple anti-atherosclerotic properties. Hence, enhanced expression of eNOS and increased Nitric oxide levels may protect against the development of atherosclerosis. Piper sarmentosum is a tropical plant with antioxidant and anti-inflammatory activities. This study aimed to investigate the effects of Piper sarmentosum on the eNOS and Nitric oxide pathway in cultured human umbilical vein endothelial cells (HUVECs).

METHODS:

HUVECs were divided into four groups: control, treatment with 180 μM hydrogen peroxide (H₂O₂), treatment with 150 μg/mL aqueous extract of Piper sarmentosum, and concomitant treatment with aqueous extract of PS and H₂O₂ for 24 hours. Subsequently, HUVECs were harvested and eNOS mRNA expression was determined using qPCR. The eNOS protein level was measured using ELISA, and the eNOS activity and Nitric oxide level were determined by the Griess reaction.

RESULTS:

Human umbilical vein endothelial cells treated with aqueous extract of Piper sarmentosum showed a marked induction of Nitric oxide. Treatment with PS also resulted in increased eNOS mRNA expression, eNOS protein level and eNOS activity in HUVECs.

CONCLUSION:

Aqueous extract of Piper sarmentosum may improve endothelial function by promoting NO production in HUVECs.     

Native low-density lipoprotein-dependent interleukin-8 production through pertussis toxin-sensitive G-protein coupled receptors and hydrogen peroxide generation contributes to migration of human aortic smooth muscle cells

Purpose

Stimulation of human aortic smooth muscle cells (hAoSMCs) with native low-density lipoprotein (nLDL) induced the production of interleukin-8 (IL-8) that is involved in the pathogenesis of cardiovascular diseases. However, the process of signal transduction of nLDL was currently uncharacterized. Therefore, the aim of this study was to investigate the signal transduction pathway of nLDL-dependent IL-8 production and the effect of IL-8 on hAoSMCs migration.

Materials and Methods

nLDL was prepared by ultracentrifugation with density-adjusted human serum of normocholesterolemia. In hAoSMCs, IL-8 secreted to medium was measured using ELISA assay, and Western blot analysis was performed to detect p38 MAPK activation as a key regulator of IL-8 production. nLDL-dependent H₂O₂ generation was determined by microscopic analysis using 2'',7''-dichlorofluoroscein diacetate (DCF-DA). IL-8-induced migration of hAoSMCs was evaluated by counting the cell numbers moved to lower chamber using Transwell plates.

Results

nLDL-induced IL-8 production was completely blocked by preincubation of hAoSMCs with pertussis toxin (PTX), which inhibited nLDL-dependent p38 MAPK phosphorylation. PTX-sensitive G-protein coupled receptor was responsible for nLDL-dependent H₂O₂ generation that was abrogated with preincubation of the cells with of polyethylene glycol-conjugated catalase (PEG-Cat). Pretreatment of PEG-Cat prevented nLDL-induced p38 MAPK phosphorylation and IL-8 production, which was partly mimicked by treatment with exogenous H₂O₂. Finally, IL-8 increased hAoSMCs migration that was completely blocked by incubation with IL-8 neutralizing antibody.

Conclusion

PTX-sensitive G-protein coupled receptor-dependent H₂O₂ generation by nLDL plays a critical role in IL-8 production in hAoSMC, and IL-8 may contribute to atherogenesis through increased migration of hAoSMCs.     

Glucocorticoids Induce Cardiac Fibrosis via Mineralocorticoid Receptor in Oxidative Stress: Contribution of Elongation Factor Eleven-Nineteen Lysine-Rich Leukemia (ELL)

Background

Cardiac fibrosis is considered to be a crucial factor in the development of heart failure. Blockade of the mineralocorticoid receptor (MR) attenuated cardiac fibrosis and improved the prognosis of patients with chronic heart failure but the ligand for MR and the regulatory mechanism of MR pathway in the diseased heart are unclear. Here, we investigated whether glucocorticoids can promote cardiac fibrosis through MR in oxidative stress and the involvement of elongation factor eleven-nineteen lysine-rich leukemia (ELL), a co-activator of MR, in this pathway.

Methods and Results

The MR antagonist eplerenone attenuated corticosterone-induced collagen synthesis assessed by [³H]proline incorporation in rat neonatal cultured cardiac fibroblasts in the presence of H₂O₂, as an oxidative stress but not in the absence of H₂O₂. H₂O₂ increased the ELL expression levels and MR-bound ELL. ELL expression levels and MR-bound ELL were also increased in the left ventricle of heart failure model rats with significant fibrosis and enhanced oxidative stress. Eplerenone did not attenuate corticosterone-induced increase of [³H]proline incorporation in the presence of H₂O₂ after knockdown of ELL expression using small interfering RNA in cardiac fibroblasts.

Conclusion

Glucocorticoids can promote cardiac fibrosis via MR in oxidative stress, and oxidative stress modulates MR response to glucocorticoids through the interaction with ELL. Preventing cardiac fibrosis by modulating glucocorticoid-MR-ELL pathway may become a new therapeutic strategy for heart failure.     

Modulation of collagen synthesis and its gene expression in human skin fibroblasts by tocotrienol-rich fraction

Introduction

Skin aging may occur as a result of increased free radicals in the body. Vitamin E, the major chain-breaking antioxidant, prevents propagation of oxidative stress, especially in biological membranes. In this study, the molecular mechanism of tocotrienol-rich fraction (TRF) in preventing oxidative stress-induced skin aging was evaluated by determining the rate of total collagen synthesis and its gene expression in human skin fibroblasts.

Material and methods

Primary culture of human skin fibroblasts was derived from circumcision foreskin of 9 to 12 year-old boys. Fibroblast cells were divided into 5 different treatment groups: untreated control, hydrogen peroxide (H₂O₂)-induced oxidative stress (20 µM H₂O₂ exposure for 2 weeks), TRF treatment, and pre- and post-treatment of TRF to H₂O₂-induced oxidative stress.

Results

Our results showed that H₂O₂-induced oxidative stress decreased the rate of total collagen synthesis and down-regulated COL I and COL III in skin fibroblasts. Pre-treatment of TRF protected against H₂O₂-induced oxidative stress as shown by increase in total collagen synthesis and up-regulation of COL I and COL III (p<0.05) genes. However, similar protective effects against H₂O₂-induced oxidative stress were not observed in the post-treated fibroblasts.

Conclusions

Tocotrienol-rich fraction protects against H₂O₂-induced oxidative stress in human skin fibroblast culture by modulating the expression of COL I and COL III genes with concomitant increase in the rate of total collagen synthesis. These findings may indicate TRF protection against oxidative stress-induced skin aging.     

Alcohol alters sensory processing to respiratory stimuli in healthy men and women during wakefulness

Study Objectives:

Alcohol can cause sleep-disordered breathing in healthy men, increase O₂ desaturation in men who snore, and worsen obstructive sleep apnea (OSA) severity in men with OSA. These findings are less consistent among women, and the underlying mechanisms are incompletely understood. Respiratory-load sensory processing, which underpins upper-airway and respiratory responses to increased breathing load, is potentially impaired by alcohol. Using respiratory-related evoked potentials (RREPs) during wakefulness, this study aimed to test the hypothesis that alcohol impairs respiratory-load sensory processing and to explore potential sex differences.

Design:

Within-subjects cross-over design in men versus women.

Setting:

Sleep physiology laboratory.

Participants:

Twenty healthy individuals (9 women) aged 18 to 38 years.

Interventions:

Within each subject, RREP waveform components were generated by ∼60 brief early-inspiratory negative-pressure pulses (−13 cm H₂O mask pressure, 200 ms) before and after acute alcohol administration (1.5 mL/kg body weight). Choanal and epiglottic pressures were recorded to monitor stimulus magnitude and upper-airway resistance.

Measurements and Results:

The latency of several RREP waveform components increased after the administration of alcohol (ΔN1 = 11 ± 5 ms, ΔN2 = 6 ± 3 ms, ΔP3 = 26 ± 10 ms), and P2 amplitude decreased (3.4 ± 1.5 μV vs 1.2 ± 0.8 μV). There were no changes in P1 latency or amplitude. During relaxed breathing, nasal resistance increased after alcohol ingestion (1.38 ± 0.16 vs 1.86 ± 0.18 cm H₂O·l^-1·s^-1), but pharyngeal and supraglottic resistances remained unchanged. RREP waveform components and upper-airway resistance measures were not different in men versus women before or after alcohol ingestion.

Conclusions:

These data demonstrate that alcohol alters sensory processing of respiratory neural information, but not early neural transmission (P1), to a similar extent in healthy men and women. Altered sensory processing to respiratory stimuli, as well as nasal congestion, may be important mechanisms contributing to alcohol-related sleep disordered breathing.

Citation:

Eckert DJ; Elgar NJ; McEvoy RD; Catcheside PG. Alcohol alters sensory processing to respiratory stimuli in healthy men and women during wakefulness. SLEEP 2010;33(10):1389-1395.     

Effect of vitamin A adjunct therapy for cerebral malaria in children admitted to Mulago hospital: a randomized controlled trial

Background

Malaria is a leading cause of mortality in Uganda accounting for 25% of deaths among children. Hitherto no adjunct therapy has been identified to improve outcome of cerebral malaria. Retinol suppresses growth of P.falciparum, scavenges free radicals, and exhibits synergistic action with quinine in parasite clearance.

Objective

To determine the effect of vitamin A supplementation on treatment outcome of cerebral malaria

Methods

In this randomised double-blind placebo controlled clinical trial we studied 142 children aged 6–59 months admitted with cerebral malaria in Mulago Hospital, Kampala. Children were randomised to either vitamin A or placebo and followed for 7 days. The main outcome measures were coma recovery time, time for convulsions to stop, and parasite and fever clearance. Secondary outcomes were overall mortality and time taken to start oral feeds.

Results

There was no difference in the coma recovery time (p=0.44), resolution of convulsions (p=0.37), fever clearance (p=0.92), parasite clearance (p=0.12), and starting oral feeds between the two treatment groups. Mortality was higher (16.2%) in the placebo than in the vitamin A group (8.1%): RR 1.4; 95% CI 1.0–2.1.

Conclusions

Vitamin A as adjunct therapy did not significantly reduce coma duration but there were fewer deaths in the vitamin A arm.     

Energy Expenditure is Affected by Rate of Accumulation of Sleep Deficit in Rats

Study Objectives:

Short sleep is a putative risk factor for obesity. However, prolonged total sleep deprivation (TSD) leads to negative energy balance and weight loss in rodents, whereas sleep-restricted humans tend to gain weight. We hypothesized that energy expenditure (V̇O₂) is influenced by the rate of accumulation of sleep deficit in rats.

Design and Intervention:

Six Sprague-Dawley rats underwent chronic sleep-restriction (CSR, 6-h sleep opportunity at ZT0-6 for 10 days) and stimulus-control protocols (CON, 12-h sleep opportunity for 10 days, matched number of stimuli) in a balanced cross-over design. Four additional rats underwent TSD (4 days). Sleep was manipulated using a motor-driven walking wheel.

Measurements and Results:

Electroencephalography, electromyography, and body temperature were measured by telemetry, and V̇O₂, by respirometry. Total sleep deficits of 55.1 ± 6.4 hours, 31.8 ± 6.8 hours, and 38.2 ± 2.3 hours accumulated over the CSR, CON, and TSD protocols, respectively. Responses to TSD confirmed previous reports of elevated V̇O₂ and body temperature. These responses were attenuated in CSR, despite a greater cumulative sleep deficit. Rate of rise of O₂ was strongly correlated with rate of accumulation of sleep deficit, above a threshold deficit of 3.6 h·day⁻¹.

Conclusion:

The change in V̇O₂ is affected by rate of accumulation of sleep deficit and not the total sleep loss accrued. Negative energy balance, observed during TSD, is strongly attenuated when brief daily sleep opportunities are available to rats (CSR), despite greater accumulated sleep deficit.

Citation:

Caron AM; Stephenson R. Energy expenditure is affected by rate of accumulation of sleep deficit in rats. SLEEP 2010;33(9):1226-1235.     

Modulation of Genioglossus Muscle Activity Across Sleep-Wake States by Histamine at the Hypoglossal Motor Pool

Study Objectives:

Histamine neurons comprise a major component of the aminergic arousal system and significantly influence sleep-wake states, with antihistamines widely used as sedative hypnotics. Unlike the serotonergic and noradrenergic components of this arousal system, however, the role of histamine in the central control of respiratory motor activity has not been determined. The aims of this study were to characterize the effects of histamine receptor agonists and antagonists at the hypoglossal motor pool on genioglossus muscle activity across sleep and awake states, and also determine if histamine contributes an endogenous excitatory drive to modulate hypoglossal motor outflow to genioglossus muscle.

Design, Participants, and Interventions:

Thirty-three rats were implanted with electroencephalogram and neck electrodes to record sleep-wake states, and genioglossus and diaphragm electrodes for respiratory muscle recordings. Microdialysis probes were inserted into the hypoglossal motor nucleus.

Measurements and Results:

Histamine at the hypoglossal motor nucleus significantly increased tonic genioglossus muscle activity in wakefulness, non-REM sleep and REM sleep. The activating effects of histamine on genioglossus muscle activity also occurred with a histamine type-1 (H₁) but not H₂ receptor agonist. However, H₁ receptor antagonism at the hypoglossal motor nucleus did not decrease genioglossus muscle activity in wakefulness or sleep.

Conclusions:

The results suggest that histamine at the hypoglossal motor pool increases genioglossus muscle activity in freely behaving rats in wakefulness, non-REM, and REM sleep via an H₁ receptor mechanism.

Citation:

Bastedo T; Chan E; Park E; Liu H; Horner RL. Modulation of genioglossus muscle activity across sleep-wake states by histamine at the hypoglossal motor pool. SLEEP 2009;32(10):1313-1324.