Nigari (deep seawater concentrate) enhances the treadmill exercise performance of gerbils.

The beneficial effect of magnesium supplementation on exercise performance has been reported by many researchers. In the present study, the effect of nigari, a concentrate of deep seawater containing high magnesium levels, on exercise performance, was examined. Gerbils were given double-distilled water or nigari (18 mg · kg(-1), po) orally 30 min before exercise. All animals were subjected to forced exercise on a treadmill for 90 min at three successive speeds of 10, 15, and 20 m · min(-1). The retention numbers were recorded. The retention numbers were 85.0 ± 21.0, 46.0 ± 9.7, and 48.0 ± 14.2 in the control group, and 44.0 ± 10.9, 23.0 ± 8.4, and 13.0 ± 4.8 in the nigari-treated group at the three speeds, respectively. The retention numbers were significantly reduced at higher speeds (by 50% at 15 and 73% at 20 m · min(-1), respectively) in the nigari-treated group when compared to those of the control group, respectively. Thus, nigari administration appeared to reduce retention numbers and enhance exercise performance in gerbils.

Correlations of AQP4 expression and polymorphism with diabetic retinopathy.

OBJECTIVE: The aim of this study was to investigate the relationships of aquaporin 4 (AQP4) rs200498749, rs149465 and rs650217 polymorphisms and gene expression with diabetic retinopathy (DR). PATIENTS AND METHODS: A total of 400 patients with diabetes mellitus (DM) treated in our hospital were enrolled in this study. All subjects were divided into two groups, including DM group (n=200, without DR) and DR group (n=200, with DR). The polymorphisms rs200498749, rs149465 and rs650217 of AQP4 gene were analyzed in the two groups. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect gene expression, and statistical analysis was performed in combination with clinical data. RESULTS: The distribution of alleles of AQP4 rs650217 (p=0.015) in DR group was different from that in DM group, and the frequency of T allele was significantly higher in DR group than DM group. The distribution of genotypes of AQP4 rs149465 (p=0.000) and rs650217 (p=0.000) showed statistically significant difference between DR group and DM group. The frequency of AA genotype of polymorphism rs149465 and CT genotype of polymorphism rs650217 was significantly higher in DR group than DM group. Besides, there was a difference in the distribution of recessive models of AQP4 rs149465 (p=0.023) and rs650217 (p=0.014) between DR group and DM group. DR group exhibited remarkably lowered frequency of AA + AT recessive model of the polymorphism rs149465 and raised frequency of CT + TT recessive model of the polymorphism rs650217. Similarly, a difference was found in the distribution of haplotypes CAT (p=0.014) and CTC (p=0.003) of AQP4 rs200498749, rs149465 and rs650217 between DR group and DM group. The polymorphism rs200498749 of AQP4 gene was significantly correlated with AQP4 gene expression (p<0.05). Meanwhile, the expression of AQP4 gene was clearly higher in patients with CC genotype in DR group (p<0.05). AQP4 polymorphism rs200498749 was related to fasting blood glucose (p=0.000) and hemoglobin A1c (HbA1c) (p=0.000) in DR group, and polymorphism rs650217 had an association with serum creatinine level (p=0.034). AQP4 polymorphisms rs149465 (p=0.023) and rs650217 (p=0.042) were correlated with clinical stage in DR group. In addition, the proportion of patients with AA genotype of rs149465 at stage VI and with TT genotype of rs650217 at stage I rose significantly (p<0.05). CONCLUSIONS: AQP4 gene polymorphism has a potential relationship with the susceptibility and progression of DR.

The impact of a leptin gene SNP on beef calf weaning weights.

Prior research indicates that a SNP at position 305 of exon 2 in the leptin gene affects milk production in dairy cows. Dairy cows with at least one copy of the T allele have been shown to have higher milk production than CC cows. If that effect carries over to beef breeds, it is reasonable to expect that CT and TT beef cows will wean heavier calves than CC beef cows. We tested this hypothesis for a herd of mixed breed cows using anova. Results indicated that both crossbred CT and TT beef cows wean significantly heavier beef calves than CC crossbred beef cows. A lack of observations generally hinders detection of significance in other breeds. However, two other comparisons were found to be significant. The results suggest further investigation into the link between leptin genotype and calf weaning weights. Aside from interest to animal scientists, these results have the potential to alter mating and replacement selection decisions by cow-calf producers, given the importance of weaning weights on profitability.

Synthesis of 1-benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole analogues as novel antiplatelet agents.

1-Benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole (28, YC-1) was selected as the lead compound for systemic structural modification. After screening for antiplatelet activity, SARs of YC-1 analogues were established. Among these potent active derivatives, compounds 29, 30, 31, 44, and 45 functioned as potent activators of sGC and inhibitors of PDE5 with potency comparable to that of YC-1. In addition, compound 58 was found to be a selective and potent inhibitor of protease-activated receptor type 4 (PAR4)-dependent platelet activation.

Involvement of catecholamines in recall of the conditioned NK cell response.

The primary goal of the study was to identify the types of catecholamines and the associated receptors which might be involved in the recall of the conditioned NK cell response. Specific catecholamine receptor antagonists were selected to block the conditioned NK cell response at the recall step. The regional contents of dopamine (DA), norepinephrine (NE), and epinephrine were determined in the brain of the conditioned animals by using the high performance liquid chromatography with electrochemical detection (HPLC/ED). Results showed that pre-disruption of the central alpha1-, alpha2-, beta1-, beta2-, D1-, or D2-receptors at the conditioned recall stage, interrupted the conditioned enhancement in NK cell activity. The NE contents at the cerebellum, and DA contents at the striatum and hippocampus, were significantly higher in the brain of the conditioned animals when compared to that of the control animals. These information indicated the possible roles of the central noradrenergic and dopaminergic systems in regulating the recall of the conditioned NK cell response.

Effect of diethylmaleate on liver extracellular glutathione levels before and after global liver ischemia in anesthetized rats.

Glutathione (GSH), present in a high concentration in the liver, serves important protective functions. We investigated the effect of lowered tissue GSH content, accomplished by diethylmaleate (DEM) administration, on liver extracellular GSH levels before and after global ischemia in anesthetized rats. Liver extracellular GSH levels were determined by microdialysis perfusion and an on-line high performance liquid chromatography system. Global liver ischemia was induced by ligation of the hepatic pedicles including the hepatic artery, portal vein, and bile duct. DEM (4 mmol/kg) significantly lowered both the liver tissue GSH levels (1.36 +/- 0.26 micromol/g wet wt vs 9.50 +/- 0.55 micromol/g wet wt for the untreated) and the liver extracellular GSH levels (4.3 +/- 2.4 microM vs 25.2 +/- 8.7 microM for the untreated). Global liver ischemia induced a dramatic increase in the liver extracellular GSH level. Although the liver tissue GSH level was lowered following DEM treatment, DEM administration did not affect significantly ischemia-induced elevation of extracellular GSH (when presented as fold increase relative to basal value). In conclusion, DEM showed a direct effect on liver extracellular GSH content in anesthetized rats. However, DEM treatment did not affect the relative release of GSH following global liver ischemia.

Dorsal facial area of cat medulla; 5-HT2 action on glutamate release in regulating common carotid blood flow.

Serotonin (5-HT) may inhibit glutamate release in the dorsal facial area (DFA) of the medulla and decrease common carotid arterial (CCA) blood flow. We attempted to clarify which subtype(s) of 5-HT receptor was involved. A microdialysis probe was inserted in DFA. The concentration of glutamate in dialysates were determined by chromatography. Glutamate concentration was dose-dependently decreased by perfusion of 5-HT or DOI, a 5-HT2 agonist, but not by 5-CT, a 5-HT1 agonist. The 5-HT-induced decrease in glutamate was reversed by co-perfusion of ketanserin, a 5-HT2 antagonist, but not by propranolol, a 5-HT1 antagonist. CCA blood flow was decreased when 5-HT or DOI was perfused, and was reversed by co-perfusing ketanserin. In conclusion, 5-HT may inhibit glutamate release via 5-HT2 receptor in DFA, resulting in the reduction of CCA blood flow.

Glial cell line-derived neurotrophic factor protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in C57BL/6 mice.

To mimic chronic exposure to neurotoxins in inducing dopaminergic cell damage, multiple doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were injected in C57BL/6 mice. Effects of pre- and post-treatment with the glial cell line-derived neurotrophic factor (GDNF) by injections into the striatum were investigated. GDNF exerts protective and reverse effects on the dopaminergic damage, supporting the potential application of GDNF in prevention and treatment of Parkinson's disease.

Systemic administration of a water-soluble hexasulfonated C(60) (FC(4)S) reduces cerebral ischemia-induced infarct volume in gerbils.

Buckminsterfullerence and its derivatives have recently been shown to exhibit considerable in vivo biological activities. A water-soluble hexasulfonated C(60) (FC(4)S) has been shown to protect against oxidative stress. Neuroprotective effects of FC(4)S were investigated in the present study. Focal cerebral ischemia was produced by a permanent occlusion of the right middle cerebral artery in gerbils. Infarct volumes were determined by 2,3,5-triphenyltetrazolium chloride transcardiac perfusion 24 h after cerebral ischemia. Chronic pretreatment of FC(4)S (0.5 and 5.0 mg/kg/day, intraperitoneally for 2 weeks) significantly reduced the infarct volume (by 42% and 68%, respectively) when compared to that of the control group. Results revealed that chronic pretreatment of FC(4)S may protect the brain against focal cerebral ischemia.

The dorsal facial area of the medulla in cats: inhibitory action of serotonin on glutamate release in regulating common carotid blood flow.

Whether glutamate and serotonin would release and interact in the dorsal facial area (DFA) of cat medulla to regulate common carotid arterial (CCA) blood flow was explored by placing a microdialysis probe in DFA and employing high performance liquid chromatographic technique. Glutamate concentration was dose-dependently decreased by perfusion with serotonin, or alaproclate, a serotonin reuptake inhibitor. Serotonin and glutamate concentrations were increased by perfusion with KCl, a depolarizing agent. Furthermore, CCA blood flow was decreased when glutamate concentration was reduced by serotonin or alaproclate perfusion, and conversely increased when glutamate concentration was increased by KCl perfusion. In conclusion, glutamate and serotonin releases in DFA that involve regulation of CCA blood flow are tonically mediated by nerve terminals. The glutamate release is depressed by the serotonin release.

Effects of naloxone on lactate, pyruvate metabolism and antioxidant enzyme activity in rat cerebral ischemia/reperfusion.

Whether naloxone may modulate energy metabolism and endogenous antioxidant enzyme activities in ischemic cortex was studied. Cerebral ischemia/reperfusion (I/R) was produced by occluding two common carotid arteries and the right middle cerebral artery for 90 min followed by reperfusion in anesthetized Sprague-Dawley rats. Both pre-treatment (0.03 or 0.3 mg) and post-treatment (0.3 mg) of naloxone by intracerebroventricular infusion significantly reduced cortical infarct volumes. Pre-treatment with 0.03 mg reduced ischemia-induced suppression of extracellular pyruvate level and enhancement of lactate/pyruvate ratio as well as cerebral I/R-induced increases of endogenous catalase, glutathione peroxidase, and manganese superoxide dismutase activities. In conclusion, neuroprotective effects of naloxone in terms of reducing brain infarction involve attenuation of the disturbance of cellular functions following cerebral I/R via restoration of mitochondrial activities or energy metabolism.

Effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and 5,7-dihydroxytryptamine on the locomotor activity and striatal amines in C57BL/6 mice.

The present study examined the effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 5,7-dihydroxytryptamine (5,7-DHT) on striatal levels of dopamine (DA), 5-hydroxytryptamine (5-HT), and their metabolites homovanillic acid (HVA) and 5-hydroxyindole-3-acetic acid (5-HIAA), respectively, as well as their influence on locomotor activity in conscious C57BL/6 mice. High doses (s.c., 35-45 mg/kg per day for 10 days) of MPTP resulted in a significant (P < 0.05) increase in locomotor activity and a marked decrease of striatal DA levels. Concomitantly, the ratios of HVA to DA and 5-HIAA to 5-HT increased significantly, the latter reflecting increased 5-HIAA levels. In contrast, i.c.v. administration of the serotonergic neurotoxin 5,7-DHT, either alone or following high doses (40 mg/kg per day for 10 days) of MPTP, decreased locomotor activity. Furthermore, striatal levels of 5-HT and 5-HIAA as well as the 5-HIAA/5-HT ratio decreased significantly. Thus, the increased locomotor activity induced by chronic high doses of MPTP might be due to increased striatal 5-HT levels which appear to compensate for the loss of DA. Furthermore, the locomotor hypoactivity induced by 5,7-DHT may be secondary to the striatal 5-HT deficiency.

Monoamines and their metabolites in plasma and lumbar cerebrospinal fluid of Chinese patients with Parkinson's disease.

Ten free monoamines and their metabolites in plasma and cerebrospinal fluid (CSF) were simultaneous measured in 6 levodopa-untreated (LU), 18 levodopa-treated (LT) and 37 levodopa-withdrawn (LW) Chinese patients with Parkinson's disease (PD) and 26 controls. We found that the levels of these substances in LW patients were not significantly different from those in LU patients. In LU- and LW-PD patients, CSF epinephrine (EPI) was higher (P < 0.05) than that of the controls. 3-methoxy-DOPA (3-OMDOPA) might not inhibit the accumulation of 3,4-dihydroxyphenylalanine (DOPA) and dopamine metabolites in CSF. Levodopa treatment might change the dopaminergic and serotoninergic neuronal systems, but not the noradrenergic or adrenergic neuronal systems, in CNS of PD patients. Benserazide (a peripheral decarboxylase inhibitor) in Madopar might decrease the levels of serotonin (5-HT) and norepinephrine (NE), but not those of DOPA and homovanillic acid (HVA), in plasma. HVA, NE and EPI in plasma were not good indices for those in CSF. Otherwise, our results were consistent with some other studies by showing a significantly lower level (P < 0.01) of HVA in CSF of LU- and LW-PD patients than that of the controls, while no difference for NE, 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindole acetic acid (5-HIAA) or 3-OMDOPA was noted. The severity of clinical disability was related to the deficiency of CSF HVA and DOPAC in LU- and LW-PD patients; however, there was no relationship between clinical symptoms of tremor, rigidity-bradykinesia, autonomic dysfunction, dementia, depression or levodopa-induced dyskinesia and CSF monoamines or their metabolites.

Studies of dementia, depression, electrophysiology and cerebrospinal fluid monoamine metabolites in patients with Parkinson's disease.

Twenty-two patients with Parkinson's disease (PD) were studied by clinical evaluation, assessments of dementia and depression, as well as electrophysiologic examinations for blink reflex (BR), cortical somatosensory evoked potentials (CSEP), brain stem, and long-latency auditory evoked potentials (BAEP, and LAEP), and cerebrospinal fluid (CSF) assays for monoamine metabolites. Results show that PD patients have a significant decrease of Mini-Mental State Examination (MMSE) scores (p < 0.05) and an increase of Hamilton Depression Scale (HDS) scores (p < 0.01), as well as a longer latencies of R2 in BR, N19 and P22 in CSEP, W4 and W5 in BAEP and P300 in LAEP (p < 0.01), and lower CSF levels of HVA and MHPG (p < 0.05). The findings suggest a correlation between dementia/depression and mesocorticolimbic and mesostriatocortic dysfunction with dopaminergic and noradrenergic deficiencies in PD patients. Furthermore, parkinsonian dementia parallels the length of duration of the disease, but not the severity of motor disability. Parkinsonian depression parallels both the length of duration of the disease and the severity of motor disability.

Determination of sunscreen agents in cosmetic products using microwave-assisted extraction and liquid chromatography.

Microwave-assisted extraction (MAE), was used to extract sunscreen agents from cosmetic products. The extracts were analyzed by liquid chromatography (LC). The present method allows the determination of three sunscreen agents, Eusolex 2292, 4360 and 6300. The precision of the assay at 40 microg/ml of sunscreen agents ranged from 1.5 to 2.2%, and the detection limits were 2.0-4.0 ng/ml.

Determination and pharmacokinetic profile of omeprazole in rat blood, brain and bile by microdialysis and high-performance liquid chromatography.

The disposition and biliary excretion of omeprazole was investigated following i.v. administration to rats at 10 mg/kg. We used a microdialysis technique coupled to a validated microbore HPLC system to monitor the levels of protein-unbound omeprazole in rat blood, brain and bile, constructing the relationship of the time course of the presence of omeprazole. Microdialysis probes were simultaneously inserted into the jugular vein toward right atrium, the brain striatum and the bile duct of the male Sprague-Dawley rats for biological fluid sampling after the administration of omeprazole (10 mg/kg) through the femoral vein. The concentration-response relationship from the present method indicated linearity (r2>0.995) over a concentration range of 0.01-50 microg/ml for omeprazole. Intra-assay and inter-assay precision and accuracy of omeprazole fell well within the predefined limits of acceptability. Following omeprazole administration, the blood-to-brain coefficient of distribution was 0.15, which was calculated as the area under the concentration versus time curve (AUC) in the brain divided by the AUC in blood (k=AUCbrain/AUCblood). The blood-to-bile coefficient of distribution (k=AUCbile/AUCblood) was 0.58. The decline of unbound omeprazole in the brain striatum, blood and bile fluid suggests that there was rapid exchange and equilibration between the compartments of the peripheral and central nervous systems. In addition, the results indicated that omeprazole was able to penetrate the blood-brain barrier and undergo hepatobiliary excretion.

Pharmacokinetic study of levofloxacin in rat blood and bile by microdialysis and high-performance liquid chromatography.

The aim of this study was to develop a rapid and sensitive method for the simultaneous determination of unbound levofloxacin in rat blood and bile using high-performance liquid chromatography coupled with microdialysis for further pharmacokinetic study. Microdialysis probes were simultaneously inserted into the jugular vein toward the right atrium and the bile duct of male Sprague-Dawley rats for biological fluid sampling after administration of levofloxacin 3 mg/kg through the femoral vein. Levofloxacin and dialysates were separated using a Merck LiChrospher reversed-phase C18 column maintained at ambient temperature. The mobile phase was comprised of acetonitrile-1 mM 1-octanesulfonic acid (40:60, v/v, pH 3.0 adjusted with orthophosphoric acid). The fluorescence response for levofloxacin was observed at excitation and emission wavelengths of 292 and 494 nm, respectively. The detection limit of levofloxacin was 50 ng/ml. Intra-day and inter-day precision and accuracy of levofloxacin measurements fell well within the predefined limits of acceptability. The disposition of levofloxacin in the blood and bile fluid suggests that there was rapid exchange and equilibration between the blood and hepatobiliary systems, and the plasma level of levofloxacin was greater than that of the bile. Thus, levofloxacin undergoes hepatobiliary excretion but might not be related to the P-glycoprotein transport system.

On-line microdialysis coupled with microbore liquid chromatography with ultraviolet detection for continuous monitoring of free cefsulodin in rat blood.

A microdialysis method followed by a microbore liquid chromatographic ultraviolet detection procedure has been performed for the assay of unbound cefsulodin in rat blood. A microdialysis probe was inserted into the jugular vein for blood sampling. This method involves an on-line design for submitting dialysate into the liquid chromatographic system. The chromatographic conditions consisted of a mobile phase of methanol-100 mM monosodium phosphoric acid (10:90, v/v, pH 5.0) pumped through a microbore reversed-phase column at a flow-rate of 0.05 ml/min. Detection wavelength was set at 265 nm. Microdialysis probes, being laboratory-made, were screened for acceptable in vivo recovery while chromatographic resolution and detection were validated for response linearity as well as intra- and inter-day variabilities. The method was then applied to pharmacokinetics profiling of cefsulodin in the blood following intravenous administration of cefsulodin (20 mg/kg) in rats. Pharmacokinetics were calculated from the corrected data for dialysate concentrations of cefsulodin versus time. Based on pharmacokinetic calculation, cefsulodin best fitted to a two-exponential disposition. This study provided specific pharmacokinetic information for protein-unbound cefsulodin and demonstrated the applicability of this continuous sampling method for pharmacokinetic study.

Determination of pyruvate and lactate in primary liver cell culture medium during hypoxia by on-line microdialysis-liquid chromatography.

A microdialysis sampling device was constructed for the measurement of pyruvate and lactate in primary liver cell culture medium during hypoxia. It was composed of a Petri dish, a dialysis membrane and two transmission tubes within a hypoxia chamber. The dialysis membrane was located in the Petri dish such that it was immersed in the culture medium. Dialysates were collected and introduced by an on-line injector to a liquid chromatographic system for analysis of pyruvate and lactate. The detection limit of this assay was 0.2-2.0 microM with acceptable intra- and inter-assay reproducibilities. In order to validate the assay, primary liver cells were incubated in the Petri dish within a hypoxia chamber in an incubator. The baseline concentrations of pyruvate and lactate in primary liver cell culture medium were 10.6+/-5.6 and 607+/-143 microM, respectively. These levels drastically changed during hypoxia and reperfusion. In conclusion, the present assay provides a sensitive, direct measurement of pyruvate and lactate in culture medium while minimizing pretreatment procedures for sample preparation.

Simultaneous monitoring of extracellular glucose, pyruvate, lactate and glutamate in gerbil cortex during focal cerebral ischemia by dual probe microdialysis.

The aim of this study was to monitor dynamic changes in energy-related metabolites in the cortex of gerbils subjected to cerebral ischemia by a dual probe microdialysis technique. Focal cerebral ischemia was produced in anesthetized gerbils by occlusion of the right common carotid artery and the right middle cerebral artery for 60 min. Two microdialysis probes were inserted into both sides of the cortex to simultaneously monitor extracellular glucose, lactate, pyruvate and glutamate. Dynamic and comparative changes in these analytes, on the ipsilateral and contralateral sides of the brain, were simultaneously monitored by liquid chromatography and a microdialysis analyzer. The present study demonstrated decreases in glucose and pyruvate, increases in lactate and glutamate on the ipsilateral side whereas all analytes remain constant on the contralateral side of cortex during cerebral ischemia. In vitro recovery of each microdialysis probe was performed to ensure the quality of experiments. The detection limits of pyruvate, glutamate, lactate and glucose were 0.2, 1.0, 2.0 and 20 microM, respectively. The intra- and inter-assay correlations were less than 5% in standard mixtures and pooled brain dialysates.