Cerebrovascular response to arousal from NREM and REM sleep

STUDY OBJECTIVE: To determine the effect of arousal from sleep on cerebral blood flow velocity (CBFV) in relation to associated ventilatory and systemic hemodynamic changes. PARTICIPANTS: Eleven healthy individuals (6 men, 5 women). MEASUREMENTS: Pulsed Doppler ultrasonography was used to measure CBFV in the middle cerebral artery with simultaneous measurements of sleep state (EEG, EOG, and EMG), ventilation (inductance plethysmography), heart rate (ECG), and arterial pressure (finger plethysmography). Arousals were induced by auditory tones (range: 40-80 dB; duration: 0.5 sec). Cardiovascular responses were examined beat-by-beat for 30 sec before and 30 sec after auditory tones. RESULTS: During NREM sleep, CBFV declined following arousals (-15% +/- 2%; group mean +/- SEM) with a nadir at 9 sec after the auditory tone, followed by a gradual return to baseline. Mean arterial pressure (MAP; +20% +/- 1%) and heart rate (HR; +17% +/- 2%) increased with peaks at 5 and 3 sec after the auditory tone, respectively. Minute ventilation (VE) was increased (+35% +/- 10%) for 2 breaths after the auditory tone. In contrast, during REM sleep, CBFV increased following arousals (+15% +/- 3%) with a peak at 3 sec. MAP (+17% +/- 2%) and HR (+15% +/- 2%) increased during arousals from REM sleep with peaks at 5 and 3 sec post tone. VE increased (+16% +/- 7%) in a smaller, more sustained manner during arousals from REM sleep. CONCLUSIONS: Arousals from NREM sleep transiently reduce CBFV, whereas arousals from REM sleep transiently increase CBFV, despite qualitatively and quantitatively similar increases in MAP, HR, and VE in the two sleep states.     

In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

ObjectiveTo investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens.MethodsWater and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC).ResultsMethanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9–22.6 mm, MIC: 200–3200 μg/mL, MBC: 200–6400 μg/mL) against all the pathogenic enteric bacteria (Vibrio cholerae, Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001).ConclusionsFor the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.     

Antiobesity,hypolipidemic, antioxidant and hepatoprotective effects of Achyranthes aspera seed saponins in high cholesterol fed albino rats

Introduction

Numerous herbal medicines have been recommended for the treatment of different diseases. Achyranthes aspera, Linn. (Family: Amaranthaceae), popularly known as Charchitta or Pitpapra, is commonly used by traditional healers for the treatment of fever, malaria, dysentery, asthma, arterial hypertension, pneumonia, and diabetes. The root extract is well reputed for its insect molting hormonal activity. This investigation was conducted to evaluate the effects of saponins from Achyranthes aspera seeds on the serum lipid profile of albino rats fed a high cholesterol diet.

Material and methods

Hypolipidemic, antioxidant and hepatoprotective activities of these saponins were tested as described previously. To determine the mechanism underlying the observed effects, serum antioxidant status was assessed according to ABTS (2,2’-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid), superoxide dismutase and ferric ion reducing antioxidant power (FRAP) assays in saponin-treated hyperlipidemic animals. Liver enzyme levels were determined to reveal any possible hepatotoxicity.

Results

Four-week oral administration of A. aspera seed saponins produced a significant (p < 0.05) decrease of total cholesterol, total triglycerides and LDL-C and a significant increase of HDL-C level in hyperlipidemic rats. Treatment with A. aspera seed saponins also showed a significant (p < 0.01) improvement of serum antioxidant status in tested animals. No significant hepatotoxicity was produced by such treatment as the serum liver enzyme activity remained unaltered.

Conclusions

Saponins from A. aspera seeds possess antihyperlipidemic and antioxidant properties which might lead to improvement of serum lipid profile and blood antioxidant status. Our findings support the folkloric use of this indigenous plant in the treatment of hyperlipidemia. However, its exact mechanism of action remains to be elucidated.