Reduction of G0 phase cells of colon cancer caco-2 cells may enhance 5-fluorouracil efficacy

Objective

A major problem in the chemotherapy of colon caner may be due to those cells that are in residence in the G₀ phase where they are less vulnerable to conventional therapy. To overcome this phenomenon, we attempted to recruit the reentry of these cells into the cell cycle via a signaling pathway that manipulates tumor growth.

Methods

Epidermal growth factor (EGF) was used to stimulate colon cancer caco-2 cells. FACS analysis and proliferating cell nuclear antigen (PCNA) staining were used to estimate the cell cycle transition and cell proliferation activated by EGF, and a MTT assay was used to evaluate the synergistic effect of EGF and chemotherapy.

Results

The percentage of caco-2 cells in the G₀/G₁ phase was significantly reduced by nearly 20% and the percentages in the S and G₂/M phases were increased by EGF. The combined use of EGF and 5-fluorouracil (5-FU) enhanced the caco-2 cell chemosensitivity to 5-FU, reaching a maximum of an approximately threefold greater sensitivity than to 5-FU alone as judged by the 50% inhibiting concentration (IC₅₀).

Conclusion

Our study demonstrated that stimulation by EGF enhanced the chemosensitivity of caco-2 cells to 5-FU, which may be a novel therapeutic protocol in colon cancer.     

A survey on the distribution of healthy people with different anti-tumour ability

Introduction

The aim of the study was to explore the distribution of healthy people with different anti-tumour ability.

Material and methods

Leukocytes were separated by the Ficoll-Hypaque density gradient centrifugal method. Then they were mixed with A549, MCF-7 and Hela cells at different ratios. The survival rate for target cells was observed and counted by Fluoroskan. Immune function for 200 healthy people was analysed by flow cytometry.

Results

The results obtained by confocal microscopy revealed that human blood leukocytes possessed direct anti-tumour activity. The survival rate for tumour cells was the lowest in the condition of 20:1 ratio of effector cells to target cells. We speculated that in 200 healthy people the leukocyte capacity for killing MCF-7 cells is stronger than the leukocyte capacity for killing A549 cells and Hela cells. We also found that the distribution for 200 healthy people with different anti-tumour ability was different for different tumour cells. The number of healthy people with the strongest anti-tumour ability was highest when the target cells were MCF-7 cells. Moreover, the survival of A549, MCF-7 and Hela cells was correlated with T, B and NK lymphocytes.

Conclusions

From the above, we can select healthy individuals with strong anti-tumour ability as anti-tumour donors according to their distribution with different anti-tumour ability, which opened up a new direction for fighting human cancer.     

Gamma-tocotrienol modulation of senescence-associated gene expression prevents cellular aging in human diploid fibroblasts

OBJECTIVE:

Human diploid fibroblasts undergo a limited number of cellular divisions in culture and progressively reach a state of irreversible growth arrest, a process termed cellular aging. The beneficial effects of vitamin E in aging have been established, but studies to determine the mechanisms of these effects are ongoing. This study determined the molecular mechanism of γ-tocotrienol, a vitamin E homolog, in the prevention of cellular aging in human diploid fibroblasts using the expression of senescence-associated genes.

METHODS:

Primary cultures of young, pre-senescent, and senescent fibroblast cells were incubated with γ-tocotrienol for 24 h. The expression levels of ELN, COL1A1, MMP1, CCND1, RB1, and IL6 genes were determined using the quantitative real-time polymerase chain reaction. Cell cycle profiles were determined using a FACSCalibur Flow Cytometer.

RESULTS:

The cell cycle was arrested in the G₀/G₁ phase, and the percentage of cells in S phase decreased with senescence. CCND1, RB1, MMP1, and IL6 were upregulated in senescent fibroblasts. A similar upregulation was not observed in young cells. Incubation with γ-tocotrienol decreased CCND1 and RB1 expression in senescent fibroblasts, decreased cell populations in the G₀/G₁ phase and increased cell populations in the G₂/M phase. γ-Tocotrienol treatment also upregulated ELN and COL1A1 and downregulated MMP1 and IL6 expression in young and senescent fibroblasts.

CONCLUSION:

γ-Tocotrienol prevented cellular aging in human diploid fibroblasts, which was indicated by the modulation of the cell cycle profile and senescence-associated gene expression.     

Respiratory Cycle-Related EEG Changes during Sleep Reflect Esophageal Pressures

Study Objectives:

Respiratory cycle-related EEG changes (RCREC) have been demonstrated during sleep by digital analysis and hypothesized to represent subtle inspiratory microarousals that may help to explain daytime sleepiness in patients with sleep-disordered breathing. We therefore examined for the first time associations between RCREC and esophageal pressure swings (ΔPes) that reflect work of breathing.

Design:

Retrospective analysis

Setting:

Academic sleep laboratory

Patients:

Forty adults referred for suspected sleep disordered breathing

Interventions:

Polysomnography with esophageal pressure monitoring and automatic computation of ΔPes using a novel algorithm.

Results:

Computed ΔPes for nearly all respiratory cycles during sleep correlated well with visual scoring of selected respiratory cycle samples (Spearman rho = 0.86, P < 0.0001). The RCREC within the sigma EEG range (12.5–15.5 Hz) rather than that within other frequency ranges most often showed significant within-subject inverse correlations with ΔPes. In contrast, in between-subject comparisons, beta (15.5–30.5 Hz) and to a lesser extent theta (4.5–7.5 Hz) RCREC, rather than sigma RCREC, showed significant inverse associations with mean ΔPes.

Conclusions:

Variation within subjects of sigma RCREC with ΔPes supports previous evidence that RCREC within this range may reflect microarousals exacerbated by increased work of breathing. Correlation of beta and theta, but not sigma RCREC with ΔPes in between-subject comparisons is more difficult to explain but suggests that ranges other than sigma also deserve further investigation for clinical utility.

Citation:

Chervin RD; Malhotra RK; Burns JW. Respiratory cycle-related EEG changes during sleep reflect esophageal pressures. SLEEP 2008;31(12):1713–1720.     

The bioload and aflatoxin content of market garri from some selected states in southern Nigeria: public health significance

Background

Garri is consumed by several millions of people in the West African sub-region and in Nigeria in particular regardless of ethnicity and socio-economic class. However production and handling methods have not been standardized resulting in a product with varying quality and safety indices hence varying public health concern.

Objectives

To investigate the microbial contamination level, presence, prevalence and distribution of Aflations B₁, B₂, G₁ and G₂ in market garri with the aim of developing useful indices for safe handling and acceptable public health standards.

Methods

A total of 300 samples comprising of 30 samples each from various market in both urban and rural settings were randomly collected using sterile polyethylene bags. These were analysed for microbiological quality and aflatoxins content using standard procedures.

Results

Eight bacteria genera (Bacillus, Staphylococcus, Streptococcus, Pseudomonas, Clostridium, Salmonella Klebsiella and Coliforms groups) genera and six fungi genera (Aspergillus, Penicillium, Rhizopus, Botrytls, Fusarium and Cladosporium) were detected and isolated. Aflatoxins B₁, B₂, G₁ and G₂ were detected in varying concentrations amongst the samples analysed within and amongst the states investigated with an average occurrence rate of 17.5%

Conclusion

Market garri was found to contain high bioload with vast array of micro-organisms and Aflatoxins in all the states investigated. Results are useful in developing and establishing public health standards for the production and safe handling of garri.     

In vivo and in vitro effects of QHF combined with chemotherapy on hepatocellular carcinoma

Objective

To investigate the synergistic anti-tumor effect of QHF (a Chinese medicine formula with anti-tumor active ingredients, including 800 mg/kg Cinobufotalin, 14 mg/kg Ginsenoside Rg3, 5.5 mg/kg Notoginseng and 100 mg/kg Lentinan) when combined with the chemotherapy drug cisplatin (DDP).

Methods

Hepatocellular carcinoma H₂₂ cells were implanted into mice and after the transplants were successfully established the animals were divided into four groups, namely a normal saline(NS) control group, QHF group, DDP group and QHF+DDP group. The tumor growth was monitored and the survival time determined. In vitro studies employing H₂₂ cells used the first three groups, and determined the effects of QHF and DDP on tumor cell cycle distribution, apoptosis and morphologic changes in vitro.

Results

QHF significantly inhibited the growth of tumors and prolonged the survival time of mice with hepatocellular carcinomas. QHF combined with DDP could attenuate DDP-induced leucopenia, spleen and thymus atrophy and other indicators of toxicity. The inhibition rate of tumor growth reached 82.54% with QHF+DDP, and QHF prolonged the life span of DDP-treated mice by 66.83%. In the in vitro experiments tumor cells showed morphological changes characteristic of apoptosis by both light and transmission electron microscopy in the QHF group, and the apoptosis rate was 33.85%. Moreover, the proportion of cells in the G₀/G₁ phase was increased and those in the S-phase decreased.

Conclusion

QHF combined with DDP could significantly inhibit tumor growth, induce the apoptosis of tumor cells and effectively attenuate DDP toxicity.     

Clinical Features and the Diagnostic Value of Component Allergen-Specific IgE in Hymenoptera Venom Allergy

Purpose

Although patient history is vital for the diagnosis of hymenoptera venom allergy, specific IgE detection is also important to identify the culprit insect and monitor the effect of immunotherapy. We evaluated the diagnostic value of serum-specific IgE detection of hymenoptera venom component allergens and documented changes in allergen-specific IgE after immunotherapy.

Methods

Fifty-six hymenoptera venom allergy patients receiving venom immunotherapy were recruited from Ajou University Hospital, Korea. The clinical manifestations of the patients were noted, and serum-specific IgE detection was performed, using conventional venom extracts as well as component allergens. Data were analyzed retrospectively.

Results

A total of 35 (62.5%) patients were male, and 33 (73.3%) patients were atopic. The mean patient age was 44.9±13.8 years. Localized reactions occurred in 23.2% of patients, and systemic reactions occurred in 76.8%. The most common clinical manifestations included skin involvement, such as urticaria and angioedema, and respiratory involvement. Yellow jackets were the most frequent culprit insect, followed by yellow hornets, white-faced hornets, honeybees, and paper wasps, as determined at the time of diagnosis. Double sensitization to both Apidae and Vespidae species was detected in 70.9% of patients. The positive predictive values (PPV) of rVes v 5-specific and rPol d 5-specific IgE detection were 85.7% and 87.5%, respectively, which correlated well with conventional venom extract-specific IgE detection (r=0.762 and r=0.757, respectively). In contrast, the PPV of rApi m 1-specific IgE detection at the time of diagnosis was 34.8%. Three years of venom immunotherapy resulted in decreased venom-specific IgE, particularly IgE specific for Vespidae venom components.

Conclusions

Stings by yellow jackets and male sex may be risk factors for hymenoptera venom allergy in Korea. Vespidae component-specific IgE, but not Apidae component-specific IgE, had diagnostic and monitoring value in hymenoptera venom allergy comparable to that of conventional hymenoptera venom extract-specific IgE.     

Construction and identification of recombinant lentiviral vector containing HIV-1 Tat gene and its expression in 293T cells

Objective

To construct a lentiviral vector expressing HIV-1 Tat and identify its expression in 293T cells.

Methods

The gene fragment of HIV-1 Tat₁₀₁ was subcloned to lentiviral transfer vector pHAGE-CMV-MCS-IZsGreen, which was named pHAGE-Tat. Then the constructed pHAGE-Tat was used to co-transfect the packing 293T cells, together with the packaging plasmids pMD2.G and psPAX2. The packaged viral particles designated LV-Tat were used to infect the 293T cells and the viral titer was calculated. The expression of HIV-1 Tat in 293T cells was confirmed using RT-PCR and western blot.

Results

The recombinant lentiviral vector was successfully constructed and could express HIV-1 Tat in 293T cells. The virus titer was 5.73×10⁶ ifu/ml.

Conclusion

The successfully constructed recombinant lentiviral vector makes a strong foundation for further exploring the possible role of HIV-1 Tat in the development of prostate cancer.     

Between-seasons test-retest reliability of clinically measured reaction time in National Collegiate Athletic Association Division I athletes

Context:

Reaction time is typically impaired after concussion. A clinical test of reaction time (RT_clin) that does not require a computer to administer may be a valuable tool to assist in concussion diagnosis and management.

Objective:

To determine the test-retest reliability of RT_clin measured over successive seasons in competitive collegiate athletes and to compare these results with a computerized measure of reaction time (RT_comp).

Design:

Case series with repeated measures.

Setting:

Preparticipation physical examinations for the football, women''s soccer, and wrestling teams at a single university.

Patients or Other Participants:

102 National Collegiate Athletic Association Division I athletes.

Interventions :

The RT_clin was measured using a measuring stick embedded in a weighted rubber disk that was released and caught as quickly as possible. The RT_comp was measured using the simple reaction time component of CogState Sport.

Main Outcome Measure(s):

Data were collected at 2 time points, 1 season apart, during preparticipation physical examinations. Outcomes were mean simple RT_clin and RT_comp.

Results:

The intraclass correlation coefficient estimates from season 1 to season 2 were 0.645 for RT_clin (n = 102, entire sample) and 0.512 for RT_comp (n = 62 athletes who had 2 consecutive valid baseline CogState Sport test sessions).

Conclusions:

The test-retest reliability of RT_clin over consecutive seasons compared favorably with that of a concurrently tested computerized measure of reaction time and with literature-based estimates of computerized reaction time measures. This finding supports the potential use of RT_clin as part of a multifaceted concussion assessment battery. Further prospective study is warranted.     

Safety and efficiency of active immunization with detoxified antigen against scorpion venom: side effect evaluation

Objective

The efficiency and safety of vaccine are the most important properties, however, as any medication, it can induce side effects. This prophylactic therapy could be used to prevent the lethal and pathophysiological effects induced after scorpion envenomation.

Methods

In this study, detoxified venom associated to alum adjuvant (V*alum) is used as a vaccine against scorpion venom for immunization of mice. We evaluate the safety and the inflammatory response of this vaccine. We also investigated the protective effect of this formulation against the toxicity of native Androctonus australis hector venom.

Results

Results showed no adverse events occurred after immunization of animals. This active immunization of animals did not cause change in vascular permeability, no edema formation in the studied organs. Furthermore, there are no IgE production in sera, nor change in the morphology of the mast cells in skin tissues. However, low inflammatory response triggered by activating the recruitment of eosinophils associated to IL-4 and IL-5 release was observed. All immunized animals are protected from the toxic effects of native venom until 6 LD50 and to 7 LD50 after the second challenge.

Conclusion

This safe vaccine preparation seems to induce a long-term protection without any risk of deleterious inflammatory response.

     

Investigation of Antioxidant Potentials of Solvent Extracts From Different Anatomical Parts of Asphodeline Anatolica E. Tuzlaci: An Endemic Plant to Turkey

Background

The genus Asphodeline (Liliaceae) is represented in Turkey by 20 taxa, which are traditionally used for medicinal purposes in Anatolia.

Materials and Methods

In this study, we tested the phytochemical content and antioxidant effect of different solvent extracts obtained from different anatomical parts of Asphodeline anatolica. The different extracts of each plant parts were tested for antioxidant activity using different chemical assays. The total antioxidant components were also calculated.

Results

Generally, acetone extracts produced the seed and root exhibited significantly higher antioxidant activity with high antioxidant components. Total phenolic content of extracts were significantly correlated with antioxidant potentials (except for, metal chelating activity).

Conclusion

On the basis of the results obtained, A. anatolica extracts should be regarded as a valuable source of natural antioxidants for food and therapeutic applications.     

Custom-molded foot-orthosis intervention and multisegment medial foot kinematics during walking

Context:

Foot-orthosis (FO) intervention to prevent and treat numerous lower extremity injuries is widely accepted clinically. However, the results of quantitative gait analyses have been equivocal. The foot models used, participants receiving intervention, and orthoses used might contribute to the variability.

Objective:

To investigate the effect of a custom-molded FO intervention on multisegment medial foot kinematics during walking in participants with low-mobile foot posture.

Design:

Crossover study.

Setting:

University biomechanics and ergonomics laboratory.

Patients or Other Participants:

Sixteen participants with low-mobile foot posture (7 men, 9 women) were assigned randomly to 1 of 2 FO groups.

Interventions :

After a 2-week period to break in the FOs, individuals participated in a gait analysis that consisted of 5 successful walking trials (1.3 to 1.4 m/s) during no-FO and FO conditions.

Main Outcome Measure(s):

Three-dimensional displacements during 4 subphases of stance (loading response, mid-stance, terminal stance, preswing) were computed for each multisegment foot model articulation.

Results:

Repeated-measures analyses of variance (ANOVAs) revealed that rearfoot complex dorsiflexion displacement during midstance was greater in the FO than the no-FO condition (F_1,14 = 5.24, P = .04, partial η² = 0.27). Terminal stance repeated-measures ANOVA results revealed insert-by-insert condition interactions for the first metatarsophalangeal joint complex (F_1,14 = 7.87, P = .01, partial η² = 0.36). However, additional follow-up analysis did not reveal differences between the no-FO and FO conditions for the balanced traditional orthosis (F_1,14 = 4.32, P = .08, partial η² = 0.38) or full-contact orthosis (F_1,14 = 4.10, P = .08, partial η² = 0.37).

Conclusions:

Greater rearfoot complex dorsiflexion during midstance associated with FO intervention may represent improved foot kinematics in people with low-mobile foot postures. Furthermore, FO intervention might partially correct dys-functional kinematic patterns associated with low-mobile foot postures.     

Temporal change in health-related quality of life: a longitudinal study in general practice 1999–2004

Background

In order to assess and plan for changing healthcare needs, the lack of available information regarding temporal changes in the health-related quality of life of a population must be addressed.

Aim

This paper aims to describe such changes over 5 years in a general population.

Design of study

Longitudinal postal questionnaire study.

Setting

UK general practice.

Method

This was a longitudinal postal questionnaire study in two general practice populations, using the generic instrument EQ-5D to measure health-related quality of life. Individuals were included if they responded to three postal surveys in 1999, 2001, and 2004 and there were three consecutive values of EQ-5D_index available between 1999 and 2004.

Results

A total of 2498 subjects were included in the study. After adjustment for potential confounders (including ageing), health-related quality of life declined significantly over the observation period. The change in EQ-5D_index was from 0.79 to 0.74 and for EQ-5D_vas 76.8 to 73.3 (P for both trends <0.001).

Conclusion

Health-related quality of life deteriorated in these populations over 5 years. In an era of improvements in mortality, this has important implications for the use of health-related quality of life data in healthcare planning and resource allocation.     

Effects of Vietnamese Sophora Root on Growth,Adhesion, Invasion and Motility of Melanoma Cells

Background

Vietnamese Sophora Root mainly contains active constituents such as alkaloids, and it has anti-tumour, antibacterial, and anti-inflammatory effects. The objective of the paper was to study the effects of Vietnamese Sophora Root on growth, adhesion, invasion and motility of mouse melanoma B₁₆BL₆ cells, and to preliminarily explore its mechanism of action.

Materials and Methods

MTT assay was used to detect the effect of Vietnamese Sophora Root aqueous extract on B₁₆BL₆ cell proliferation. Cell adhesion assay, reconstituted basement membrane invasion assay and chemotactic motility assay were used to observe the effects of Vietnamese Sophora Root aqueous extract on adhesion, invasion and motility of B₁₆BL₆ cells.

Results

Different concentrations of Vietnamese Sophora Root aqueous extracts had different degrees of inhibitory effects on B₁₆BL₆ proliferation. With the decrease of concentration, the proliferation inhibitory effect decreased and even turned to promoting effect. The extract significantly inhibited the adhesion of B₁₆BL₆ cells to the basement membrane component LN, and had a significant effect on both the invasive and migratory capacities of B₁₆BL₆ cells through the basement membrane.

Conclusion

We concluded that the aqueous extract of Vietnamese Sophora Root can inhibit the proliferation of melanoma cells, as well as their adhesion and movement.     

Assessment of antibacterial activity of crude leaf and root extracts of Cassia alata against Neisseria gonorrhea

Background

Gonorrhea is a major sexually transmitted disease worldwide and for its control, effective treatment is essential. However as more strains of Neisseria gonorrhoeae continuously develop resistance to several drugs, this strategy obliges scientists to discover newer effective drugs.

Objectives

To ascertain whether crude leaf and root extracts of Cassia alata (Caesalpiniaceae) have antimicrobial activity against clinically resistant Neisseria gonorrhoeae bacteria. To determine and compare the MICs of their ether and methanol extracts.

Materials and methods

Ether and methanol extracts were prepared from the plant parts. 12–375mg/ml of serially diluted ether extracts in DMSO and methanol extracts in water were tested using agar-well diffusion method against Neisseria gonorrhea clinical isolate cultured on MTM agar. MICs were determined from corresponding concentration-response curves. Ceftriaxone was used as positive control, whereas DMSO and water as negative controls.

Results

All the crude extracts showed concentration-dependent Neisseria gonorrhea inhibition. Ether extracts for both leaves and roots gave lower MICs compared to those of methanol. Ether root extract showed the highest potency.

Conclusions

Both the leaf and the root of Cassia alata plant have activity against clinically resistant Neisseria gonorrhoeae; the root having the higher activity. Lipophilic solvent, ether, give more potent antigonorrhoeal extracts. As expected Cassia alata plant in Central Uganda also has antibacterial activity.     

Basal Metabolic Rate in Narcoleptic Patients

Study Objectives:

We investigated basal metabolic rate (BMR) and energy expenditure (EE) in narcoleptic patients and in BMI- and age-matched controls in order to explore the hypothesis that a reduced BMR or EE plays a role in narcolepsy-associated obesity.

Design:

Control group design with comparison of EE and BMR. EE was determined by indirect calorimetry using the Deltatrac Metabolic Monitor system. BMR was calculated from the oxygen consumption (VO₂) and the carbon dioxide consumption (VCO₂) measurements after 12 hours of fasting in the morning.

Participants:

13 narcoleptic patients and 30 controls.

Results:

BMR and EE were not significantly reduced when all subjects were included into the analysis. Subgroup analysis revealed that only non-obese narcoleptics, but not obese narcoleptics had reduced BMRs in comparison to the BMI matched controls.

Conclusion:

Our study suggests that EE plays a role in narcolepsy associated obesity. We propose that narcolepsy may lead to a shift of individual BMI set points.

Citation:

Dahmen N; Tonn P; Messroghli L; Ghezel-Ahmadi D; Engel A. Basal metabolic rate in narcoleptic patients. SLEEP 2009;32(7):962-964.     

Cytotoxicity of Three South African Medicinal Plants Using the Chang Liver Cell Line

Background

Arctotis arctotoides, Gasteria bicolor and Pittosporum viridiflorum are commonly used in the Eastern Cape, South Africa by traditional healers for the treatment of opportunistic fungal infections in HIV/AIDS patients. Unfortunately, there is a dearth of published data regarding the toxicity of the selected plants, despite the fact that experimental screening of toxicity is crucial to guarantee the safety of the users.

Materials and Methods

Therefore, it was decided to evaluate the cytotoxicity of the hexane and acetone extracts of the medicinal plants against the Chang Liver cell line using the in vitro MTT assay. Different concentrations of the extracts were added into 24-hour cultured cells and incubated for 72 hours under specific condition (37 °C, 5% CO2). Cell survival was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.

Results

Depending on the dosage and duration of treatment, the cytotoxic effects of Gasteria bicolor and Pittosporum viridiflorum were considered relatively weak (but not entirely absent) and less of a toxicity risk. Arctotis arctotoides extracts were the most toxic both in terms of IC₅₀ values as well as the steeper slope of the dose response curve. The IC50 values for the acetone and hexane extracts of this plant were 17.4 and 12.4 µg/ml respectively.

Conclusion

These relatively low values raise concern for potential hepatotoxic effects and deserve further investigation or at least a warning to potential users.     

Aging Effects on Cardiac and Respiratory Dynamics in Healthy Subjects across Sleep Stages

Study Objectives:

Respiratory and heart rate variability exhibit fractal scaling behavior on certain time scales. We studied the short-term and long-term correlation properties of heartbeat and breathing-interval data from disease-free subjects focusing on the age-dependent fractal organization. We also studied differences across sleep stages and night-time wake and investigated quasi-periodic variations associated with cardiac risk.

Design:

Full-night polysomnograms were recorded during 2 nights, including electrocardiogram and oronasal airflow.

Setting:

Data were collected in 7 laboratories in 5 European countries.

Participants:

180 subjects without health complaints (85 males, 95 females) aged from 20 to 89 years.

Interventions:

None.

Measurements and Results:

Short-term correlations in heartbeat intervals measured by the detrended fluctuation analysis (DFA) exponent α₁ show characteristic age dependence with a maximum around 50–60 years disregarding the dependence on sleep and wake states. Long-term correlations measured by α₂ differ in NREM sleep when compared with REM sleep and wake, besides weak age dependence. Results for respiratory intervals are similar to those for α₂ of heartbeat intervals. Deceleration capacity (DC) decreases with age; it is lower during REM and deep sleep (compared with light sleep and wake).

Conclusion:

The age dependence of α₁ should be considered when using this value for diagnostic purposes in post-infarction patients. Pronounced long-term correlations (larger α₂) for heartbeat and respiration during REM sleep and wake indicate an enhanced control of higher brain regions, which is absent during NREM sleep. Reduced DC possibly indicates an increased cardiovascular risk with aging and during REM and deep sleep.

Citation:

Schumann AY; Bartsch RP; Penzel T; Ivanov PC; Kantelhardt JW. Aging effects on cardiac and respiratory dynamics in healthy subjects across sleep stages. SLEEP 2010;33(7):943-955.     

Antioxidant Activities and Tyrosinase Inhibition Effects of Phaleria Macrocarpa Extracts

Background

The ethyl acetate and chloroform extracts of stems, leaves and fruits of Phaleria macrocarpa were screened for their antioxidant capacity and tyrosinase inhibition properties.

Material and Method

The total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric-ion reducing power (FRAP) were used to evaluate their antioxidant capacity. Tyrosinase inhibition effect was measured using mushroom tyrosinase inhibition assay.

Result

Ethyl acetate extract of P. macrocarpa''s stem exhibited highest total phenolic content, DPPH free radical scavenging and ferric reducing power. Meanwhile, chloroform extracts of leaves and fruits demonstrated potent anti-tyrosinase activities as compared to a well-known tyrosinase inhibitor, kojic acid.

Conclusion

Since chloroform extracts of leaves and fruits have low antioxidant capacities, the tyrosinase inhibition effect observed are antioxidant independent. This study suggests direct tyrosinase inhibition by chloroform extracts of Phaleria macrocarpa.