Sludge conditioning by using alumina nanoparticles and polyelectrolyte.

The combined use of nanoparticle and polyelectrolyte as retention aids in pulp and paper industry tend to give better flocculation (retention) and drainage (dewatering) than conventional polyelectrolyte flocculation. The combined use of alumina nanoparticle and polyelectrolyte in conditioning waste activated sludge was investigated in the current study. Alumina with three different sizes (139.5, 241.7, and 326.4 nm) was utilized in combination with a cationic polyelectrolyte (T3052) of molecular weight of 1.1 x 10(7) and charge density of 2.1 meq/g. It was found from capillary suction time (CST) and specific resistance to filtration (SRF) measurement that sludge conditioned with alumina/polyelectrolyte showed a better dewaterability than polyelectrolyte alone. In addition, it was found that the better dewaterability was obtained as alumina became smaller. Floc size and fractal dimension of flocs were examined as well. The mechanism of enhanced dewaterability was proposed that alumina nanoparticles became adsorbed onto sludge and positive patches were formed. The electrostatic repulsion made the polyelectrolyte more stretched, and resulted in more effective flocculation and bridging as polyelectrolyte was added. Dosing sequence also affected the conditioning effectiveness. However, the combined use of silica nanoparticles and a cationic polelectrolyte, KP-201C, or alumina nanoparticles and an anionic polyelectrolyte, AP410, did not result in improved dewaterability of waste activated sludge. Possible explanation was discussed. Preliminary results show that some in-depth work is needed regarding the introduction of nanoparticles in sludge conditioning.

Inhibitory effect of stevioside on calcium influx to produce antihypertension.

Stevioside is a sweet-tasting glycoside occurring abundantly in the leaves of Stevia rebaudiana (Compositae). It has been used popularly in Japan and Brazil as a sugar substitute for decades. Previous study has shown that it lowered blood pressure in spontaneously hypertensive rats (SHRs) when administered intravenously. This study shows that intraperitoneal injection of stevioside 25 mg/kg also has antihypertensive effect in SHRs. In isolated aortic rings from normal rats, stevioside could dose-dependently relax the vasopressin-induced vasoconstriction in both the presence and absence of endothelium. However, stevioside had no effect on phenylephrine- and KCl-induced phasic vasoconstriction. In addition, stevioside lost its influence on vasopressin-induced vasoconstriction in Ca(2+)-free medium. The results indicate that stevioside caused vasorelaxation via an inhibition of Ca(2+) influx into the blood vessel. This phenomenon was further confirmed in cultured aortic smooth muscle cells (A7r5). Using 10(-5) M methylene blue for 15 min, stevioside could still relax 10(-8) M vasopressin-induced vasoconstriction in isolated rat aortic rings, showing that this vasorelaxation effect was not related to nitric oxide. The present data show that the vasorelexation effect of stevioside was mediated mainly through Ca(2+) influx inhibition.

The in vitro inhibitory effect of flavonoid astilbin on 3-hydroxy-3-methylglutaryl coenzyme A reductase on Vero cells.

BACKGROUND: Epidemiological studies have shown that hypercholesterolemia is a major risk factor for coronary heart disease. In clinical trials of lipid lowering therapy, 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase inhibitor has been shown to decrease cardiac events and mortality. Flavonoids are polyphenolic natural antioxidants existing in vegetables, fruits and beverages such as tea and wine. Previous studies have shown that some antioxidants had hypocholesterolemic effect, and flavonoid intake was associated with the decrease of mortality from coronary artery disease. The aim of this study was to evaluate the inhibitory effect of flavonoids on HMG-CoA reductase. METHODS: The methods for analysis of specific inhibitors of mevalonate biosynthesis have been well-established, using Vero cells, a cell line obtained from kidneys of African green monkeys. Flavonoids isolated from different traditional Chinese herbs were dissolved in DMSO and incubated with Vero cells with or without the addition of 1 mM mevalonate or 5 mM sodium acetate in order to observe cell growth for 24 h. RESULTS: Concentrations of 1 mM mevalonate or 5 mM sodium acetate were added into culture medium in order to observe the effect on cell growth. Different concentrations of pravastatin to inhibit cell growth were used as a positive control. About 40 flavonoid compounds were used for study, only one compound, astilbin (belonging to the flavonol group), showed significant inhibition of Vero cell growth. CONCLUSIONS: This study shows that one flavonoid compound, isolated from traditional medicinal herbs, may be an effective HMG-CoA reductase inhibitor which might be developed into a new hypocholesterolemic agent.

Episodic evolution of growth hormone in primates and emergence of the species specificity of human growth hormone receptor.

Growth hormone (GH) evolution is very conservative among mammals, except for primates and ruminant artiodactyls. In fact, most known mammalian GH sequences differ from the inferred ancestral mammalian sequence by only a few amino acids. In contrast, the human GH sequence differs from the inferred ancestral sequence by 59 amino acids. However, it is not known when this rapid evolution of GH occurred during primate evolution or whether it was due to positive selection. Also, human growth hormone receptor (GHR) displays species specificity; i.e., it can interact only with human (or rhesus monkey) GH, not with nonprimate GHS: The species specificity of human GHR is largely due to the Leu-->Arg change at position 43, and it has been hypothesized that this change must have been preceded by the His-->Asp change at position 171 of GH. Is this hypothesis true? And when did these changes occur? To address the above issues, we sequenced GH and GHR genes in prosimians and simians. Our data supported the above hypothesis and revealed that the species specificity of human GHR actually emerged in the common ancestor of Old World primates, but the transitional phase still persists in New World monkeys. Our data showed that the rapid evolution of primate GH occurred during a relatively short period (in the common ancestor of higher primates) and that the rate of change was especially high at functionally important sites, suggesting positive selection. However, the nonsynonymous rate/synonymous rate ratio at these sites was <1, so relaxation of purifying selection might have played a role in the rapid evolution of the GH gene in simians, possibly as a result of multiple gene duplications. Similar to GH, GHR displayed an accelerated rate of evolution in primates. Our data revealed proportionally more amino acid replacements at the functionally important sites in both GH and GHR in simians but, surprisingly, showed few coincidental replacements of amino acids forming the same intermolecular contacts between the two proteins.

Enhanced biodegradation of petrochemical wastewater using ozonation and BAC advanced treatment system.

The characteristics of degradation/conversion of bio-refractory and the growth of a biofilm are investigated in laboratory-scale pre-ozonation and lifted moving-bed biological activated carbon (BAC) advanced treatment processes treating phenol, benzoic acid, aminobenzoic acid and petrochemical industry wastewater which contains acrylonitrile butadiene styrene (ABS). The optimal reaction time and ozone dosage of pre-ozonation for bio-refractory conversion were determined to be 30 min and 100-200 mg O3/hr, respectively. After pre-ozonation of 30 min treatment, BOD5/COD ratio of influent and effluent increased apparently from 20 to 35%, approximately. However, the change of pH in pre-ozonation was inconspicuous. The optimal flow rate of influent and air were controlled at 1.6 l/h and 120-150 nl/min in lifted moving-bed BAC advanced treatment reactor. A COD removal efficiency of 85-95% and 70-90% may be maintained by using an organic loading of 3.2-6.3 kg COD/m3 day and 0.6-1.6 kg-COD/m3 day with an HRT of 6.0 h as secondary and advanced treatment system, respectively. The time required for the BAC bed is be regenerated by a thermal regeneration is prolonged 4-5 times more than that of GAC system. It can be estimated that the enhanced COD removal capability of the biofilm was not only due to the increase in the COD removal capability of acclimated bacteria, but also due to species succession of bacteria in bio-film ecosystem.

[Study on the effect of hyperbaric oxygen on apoptosis in the CA1 region of hippocampus following forebrain ischemia reperfusion].

AIM AND METHODS: To study the mechanism of hyperbaric oxygen (HBO) on the treatment of cerebral ischemia, and to provide theoretical basis for hyperbaric oxygen treatment (HBOT), we examined the effect of 0.15 MPa and 0.25 MPa HBO treatment (60 min/d, for 3 successive days ) on ischemia reperfusion - induced apoptosis in gerbil hippocampus CA1 using TUNEL staining method. RESULTS: The number of neuronal apoptosis in hippocampus CA1 was significantly decreased in HBOT groups(P < 0.01). Neuronal apoptosis in hippocampus CA1 in 0.25 MPa groups were less than that in 0.15 MPa groups (P < 0.01). CONCLUSION: HBOT is effective in reducing neuronal apoptosis and in protecting neurons from injury of ischemia reperfusion, and 0.25 MPa is an appropriate pressure for HBOT.

A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension.

AIMS: Stevioside is a natural plant glycoside isolated from the plant Stevia rebaudiana which has been commercialized as a sweetener in Japan for more than 20 years. Previous animal studies have shown that stevioside has an antihypertensive effect. This study was to designed to evaluate the effect of stevioside in human hypertension. METHODS: A multicentre, randomized, double-blind, placebo-controlled study was undertaken. This study group consisted of 106 Chinese hypertensive subjects with diastolic blood pressure between 95 and 110 mmHg and ages ranging from 28 to 75 years with 60 subjects (men 34, women 26; mean +/- s.d., 54.1+/-3.8 years) allocated to active treatment and 46 (men 19, women 27; mean +/- s.d., 53.7+/-4.1 years) to placebo treatment. Each subject was given capsules containing stevioside (250 mg) or placebo thrice daily and followed-up at monthly intervals for 1 year. RESULTS: After 3 months, the systolic and diastolic blood pressure of the stevioside group decreased significantly (systolic: 166.0+/-9.4-152.6+/-6.8 mmHg; diastolic: 104.7 +/- 5.2-90.3+/-3.6 mmHg, P<0.05), and the effect persisted during the whole year. Blood biochemistry parameters including lipid and glucose showed no significant changes. No significant adverse effect was observed and quality of life assessment showed no deterioration. CONCLUSIONS: This study shows that oral stevioside is a well tolerated and effective modality that may be considered as an alternative or supplementary therapy for patients with hypertension.

Changes in superoxide dismutase activity and mRNA in vivo after short-term supplementation with trilinolein in rats.

BACKGROUND: Oxidative damage plays a central role in atherogenesis and antioxidation defense mechanisms may prevent atherosclerosis. This study evaluated the effect of short-term supplementation of the natural lipophilic antioxidant trilinolein on superoxide dismutase (SOD) activity and SOD-mRNA gene expression in vivo in rat vital organs. METHODS: Male Wistar rats (n = 8) were injected intraperitoneally with trilinolein (1 mM/ml/kg/day in 0.5% ethanol) daily for three consecutive days. Two control groups (n = 8) were administered saline or 0.5% ethanol in saline, respectively, for three days. RESULTS: Assay of SOD activity and SOD-mRNA by Northern blotting in rat liver, spleen and brain showed significant increases in SOD activity and increased SOD-mRNA gene expression. CONCLUSIONS: The natural lipophilic antioxidant trilinolein potentiates the SOD antioxidation defense mechanism and increases gene expression of SOD-mRNA after short-term supplementation in rats.

[Effect of hyperbaric oxygen on the expression of proteins Bcl-2 and Bax in the gerbil hippocampus CA1 following forebrain ischemia reperfusion].

AIM: To study the mechanisms of how hyperbaric oxygen treatment (HBOT) reduced neuronal apoptosis following forebrain ischemia reperfusion. METHODS: Changes of the expression of protein Bcl-2 or Bax were observed in CA1 region of gerbil hippocampus following HBOT on ischemia reperfusion 3 days using the method of labelled streptavidin biotin (LSAB) immunohistochemistry staining. For this purpose gerbils were exposed to the 0.15 MPa and 0.25 MPa HBO 60 min every day for 3 successive days. RESULTS: The expression of protein Bcl-2 in hippocampus CA1 was significantly increased in HBOT groups (P < 0.01), and changes in 0.25 MPa groups were greater than those in 0.15 MPa groups (P < 0.01). The expression of protein Bax in hippocampus CA1 was not changed significantly in HBOT groups. CONCLUSION: HBO can induce the expression of Bcl-2, which is the mechanism of neuronal protecting effect of HBOT.

The antihypertensive effect of the berberine derivative 6-protoberberine in spontaneously hypertensive rats.

Berberine is a natural isoquinoline alkaloid found in plants of the Ranunculaceae and Berberidaceae families. Extracts from berberine-containing plants have been used as traditional Chinese folk remedies for centuries. The antihypertensive effects of the berberine derivative 6-protoberberine (PTB-6) were studied in spontaneously hypertensive rats (SHRs). In conscious SHRs, PTB-6 lowered the systolic blood pressure in a dose-dependent manner (6-PTB: 5 mg/kg, -31.1 +/- 1.6 mm Hg; 10 mg/kg, -42.4 +/- 3.1 mm Hg). Cardiac output using the thermodilution method was reduced in PTB-6-treated anesthetized SHRs with a tendency to decrease in heart rate. Injection of PTB-6 into the intracerebral ventricles of SHRs lowered the systolic arterial blood pressure and heart rate. The berberine derivative PTB-6 is an effective antihypertensive agent. The mechanism of the antihypertensive effect of PTB-6 is probably through a central sympatholytic effect.

[Changes and its measurement of intracellular Ca2+ during exposure to hyperbaric oxygen].

Objective. To investigate the rule of change of intracellular Ca2+ and its measurement method during exposure to hyperbaric oxygen (HBO). Method. Microfluorescence method was used to measure the changes of intracellular Ca2+ concentration in co-cultured endothelial cells (EC) and smooth muscle cells (SMC) in a specially designed miniature oxygen chamber. Result. (1) [Ca2+]i changes during HBO exposure can be clearly observed directly in the chamber. (2) Within 5 min during 0.2 MPa and 0.3 MPa HBO exposure, EC[Ca2+]i and SMC[Ca2+]i showed a tendency, to increase at first and then decrease with time throughout the exposures, especially the SMC[Ca2+]i. The EC ruptured under exposure to 0.4 MPa HBO. Conclusion. During HBO exposure, EC[Ca2+]i and SMC[Ca2+]i showed biphasic changes, which increased at first and then decreased. The technique and method used were reliable and suitable for investigating of intracellular [Ca2+]i changes under HBO.

Topical bupivacaine and proparacaine: a comparison of toxicity, onset of action, and duration of action.

Bupivacaine is a local ocular anesthetic with a long duration of action when administered by retrobulbar injection. To determine the potential for the use of bupivacaine as a topical ocular anesthetic, the onset and duration of action and toxicity of various concentrations of bupivacaine were studied after instillation in rabbit eyes. The onset and duration of action were not significantly different from that of topical 0.5% proparacaine. Increasing the pH of the bupivacaine solution from 5.7 to 6.5 nearly doubled the duration of action, but the increase was not sufficient to be clinically important. Slit lamp biomicroscopic examination and scanning electron microscopy showed that bupivacaine was less toxic to the corneal epithelium than 0.5% proparacaine. Healing after keratectomy was significantly more rapid in eyes treated with 0.75% bupivacaine, compared with eyes treated with 0.5% proparacaine. These results suggest that bupivacaine may be less toxic to the corneal epithelium than proparacaine and could be clinically useful for topical ocular anesthesia, particularly if pharmacologic modifications can increase the duration of anesthesia provided by this drug.

Intravitreal injection of piperacillin.

Piperacillin was injected into the vitreous body of rabbit eyes to evaluate its suitability for intraocular injection and its toxicity on intraocular tissues. Doses ranged from 50 micrograms to 3,000 micrograms. Toxicity was determined through histology and electroretinograms by comparing the piperacillin-injected eyes with eyes injected with balanced saline solution. Retinal toxicity was noted in the outer layer of the retina when 3,000 micrograms was injected intravitreally. No toxicity was noted by histology with 1,500 micrograms of piperacillin. The minimal inhibitory concentration of piperacillin is 800 micrograms/cc for both gram negative and gram positive organisms. The large dose of intravitreal piperacillin tolerated by rabbit eyes makes piperacillin a potentially safe and effective broad spectrum antibiotic for the treatment of bacterial endophthalmitis in human eyes.

Adsorption of phosphate by aluminum hydroxycarbonate.

Phosphate is specifically adsorbed by aluminum hydroxycarbonate by anion ligand exchange. IR analysis indicated that phosphate exchanged with specifically adsorbed carbonate. Adsorption is favored by low pH and is inversely related to particle size. Adsorption of phosphate decreases the rate of acid neutralization of aluminum hydroxycarbonate. The results are applied to the treatment of hyperphosphatemia and hypophosphatemia.

Extrahypothalamic heat gain responses in the decerebrate and spinal monkey.

In the present study it was found in Taiwan rock-monkeys as well as in cats and squirrel monkeys, that heat gain thermoregulatory mechanisms were activated after destruction of connection from the hypothalamus to the brain stem and/or spinal cord. The findings suggest that heat gain physiological mechanisms could be represented and re-represented at different levels of neuraxis: hypothalamus, brain stem and spinal cord. This concept was supported by the fact that the three levels have their own thermoresponsive cells and the cells of one level can act independently or in an integrated manner with those of the other levels. Therefore, this study would be a good model for future research to determined in physiological and behavior complexities of the multiple representation of thermoregulatory mechanisms.