Association of use of Chinese herbal medicines and the risk of fracture in patients with osteoporosis: a population-based cohort study.

After utilizing a large population-based claims database and the application of propensity score match approach to reduce the confounding effects, we found that the use of Chinese herbal medicines (CHMs) was related to the lower risk of sequent osteoporotic fracture by 27% among the individuals with osteoporosis. The predominant effect was observed in those receiving CHMs for more than two years. INTRODUCTION: Osteoporosis (OS) is a highly disabling condition that can lead to fragility fracture, thus posing greater burdens of functional limitations for the affected individuals. It is unclear if the use of Chinese herbal medicines (CHMs) could reduce the risk of fracture due to OS. This study aimed to investigate the association of CHMs and the subsequent osteoporotic fracture risk among OS patients. METHODS: This longitudinal cohort study used the Taiwanese National Health Insurance Research Database to identify 250,699 newly diagnosed OS patients aged 20 years or older between 1998 and 2010. We recruited 103,325 CHM users following the onset of OS (CHM users) and randomly selected 103,325 subjects without CHM usage as controls (non-CHM users) by propensity score matching according to the demographic characteristics and comorbidities at enrollment. All enrollees were followed until the end of 2012 to record the incidence of osteoporotic fracture. We applied the Cox proportional hazard regression model to compute the hazard ratio (HR) of the risk of osteoporotic fracture. RESULTS: During the 15-year follow-up period, 7208 CHM users and 11,453 non-CHM users sustained osteoporotic fracture, with an incidence rate of 9.26 and 12.96, respectively, per 1000 person-years. We found that CHM users had a significantly reduced risk of osteoporotic fracture compared to non-CHM users (adjusted HR 0.73; 95% confidence interval [CI] = 0.70-0.75). Those treated with CHMs for longer than 730 days had a lower fracture risk by 54%. Some commonly used CHMs, such as Yan hu suo (Rhizoma Corydalis), Huang Qin (Scutellaria Baicale), Jie Geng (Platycodon grandifloras), Xiang Fu (Cyperus rotundus), Hai Piao Xiao (Cuttlebone Sepium), Jia-Wei-Xiao-Yao-San, Ge-Gen-Tang, Shao-Yao-Gan-Cao-Tang, and Du-Huo-Ji-Sheng-Tang, are related to the lower risk of fracture. CONCLUSIONS: The use of CHMs was associated with lower risk of osteoporotic fracture for OS patients, suggesting that it could be integrated into conventional therapy to prevent subsequent bone fracture.

Astragalus polysaccharides improve cardiomyopathy in STZ-induced diabetic mice and heterozygous (SOD2+/-) knockout mice.

Oxidative stress plays an important role in the development of diabetic cardiomyopathy. In the present study, we determined whether the effect of astragalus polysaccharides (APS) on diabetic cardiomyopathy was associated with its impact on oxidative stress. Streptozotocin (STZ)-induced diabetic mice and heterozygous superoxide dismutase (SOD2+/-) knockout mice were administered APS. The hemodynamics, cardiac ultrastructure, and the apoptosis, necrosis and proliferation of cardiomyocytes were assessed to evaluate the effect of APS on diabetic and oxidative cardiomyopathy. Furthermore, H2O2 formation, oxidative stress/damage, and SOD activity in cardiomyocytes were evaluated to determine the effects of APS on cardiac oxidative stress. APS therapy improved hemodynamics and myocardial ultrastructure with reduced apoptosis/necrosis, and enhanced proliferation in cardiomyocytes from both STZ-induced diabetic mice and heterozygous SOD2+/- knockout mice. In addition, APS therapy reduced H2O2 formation and oxidative stress/damage, and enhanced SOD activity in both groups of mice. Our findings suggest that APS had benefits in diabetic cardiomyopathy, which may be partly associated with its impact on cardiac oxidative stress.

Bovine lactoferricin B induces apoptosis of human gastric cancer cell line AGS by inhibition of autophagy at a late stage.

Gastric cancer is one of the most common malignant cancers, with poor prognosis and high mortality rates worldwide. Therefore, development of an effective therapeutic method without side effects is an urgent need. It has been reported that cationic antimicrobial peptides can selectively bind to negatively charged prokaryotic and cancer cell membranes and exert cytotoxicity without causing severe drug resistance. In the current study, we prepared a series of peptide fragments derived from bovine lactoferrin and evaluated their anticancer potency toward the gastric cancer cell line AGS. Cell viability assay revealed that a 25-AA peptide fragment, lactoferricin B25 (LFcinB25), exhibited the most potent anticancer capability against AGS cells. Lactoferricin B25 selectively inhibited AGS cell growth in a dose-dependent manner, exhibiting a half-maximal inhibitory concentration (IC50) value of 64 µM. Flow cytometry showed a notable increment of the sub-G1 populations of the cell cycle, indicating the induction of apoptosis by LFcinB25. Western blot analysis further revealed that upon LFcinB25 treatment for 2 to 6h, apoptosis-related caspases-3, 7, 8, 9, and poly(ADP-ribose) polymerase (PARP) were cleaved and activated, whereas autophagy-related LC3-II and beclin-1 were concomitantly increased. Thus, both apoptosis and autophagy are involved in the early stage of LFcinB25-induced cell death of AGS cells. However, upon treatment with LFcinB25 for 12 to 24h, LC3-II began to decrease, whereas cleaved beclin-1 increased in a time-dependent manner, suggesting that consecutive activation of caspases cleaved beclin-1 to inhibit autophagy, thus enhancing apoptosis at the final stage. These findings provide support for future application of LFcinB25 as a potential therapeutic agent for gastric cancer.

The antioxidant activities of natural sweeteners, mogrosides, from fruits of Siraitia grosvenori.

To search for antioxidant agents from natural resources, in this paper the in vitro antioxidant activities of two natural sweeteners, mogroside V and 11-oxo-mogroside V isolated from the fruits of Siraitia grosvenori, were determined using chemiluminescence (CL). The results showed that these sweet glycosides, having cucurbitane triterpenoid aglycon, exhibited significant inhibitory effects on reactive oxygen species (O2-, H2O2 and *OH) and DNA oxidative damage. 11-oxo-mogroside V showed a higher scavenging effect on O2- (concentration at which 50% of chemiluminescence intensity is inhibited [EC50] =4.79 microg/ml) and H2O2 (EC50 = 16.52 microg/ml) than those of mogroside V. However, mogroside V was more effective in scavenging *OH, with EC50 =48.44 microg/ml compared with that of 11-oxo-mogroside V (EC50 = 146.17 microg/ml). Further, 11 -oxo-mogroside V exhibited a remarkable inhibitory effect on *OH-induced DNA damage with EC50 = 3.09 microg/ml.

Suppression of fatty acid synthase in MCF-7 breast cancer cells by tea and tea polyphenols: a possible mechanism for their hypolipidemic effects.

Tea is a heavily consumed beverage world wide because of its unique aroma, less cost and broad availability. Fatty acid synthase (FAS) is a key enzyme in lipogenesis. FAS is overexpressed in the malignant human breast carcinoma MCF-7 cells and its expression is further enhanced by the epidermal growth factor (EGF). The EGF-induced expression of FAS was inhibited by green and black tea extracts. The expression of FAS was also suppressed by the tea polyphenol (-)-epigallocatechin 3-gallate (EGCG), theaflavin (TF-1), TF-2 and theaflavin 3,3'-digallate(TF-3) at both protein and mRNA levels that may lead to the inhibition of cell lipogenesis and proliferation. Both EGCG and TF-3 inhibit the activation of Akt and block the binding of Sp-1 to its target site. Furthermore, the EGF-induced biosyntheses of lipids and cell proliferation were significantly suppressed by EGCG and TF-3. These findings suggest that tea polyphenols suppress FAS expression by downregulating EGF receptor/PI3K/Akt/Sp-1 signal transduction pathway, and tea and tea polyphenols might induce hypolipidemic and antiproliferative effects by suppressing FAS.

A multiobjective model for non-point source pollution control for an off-stream reservoir catchment.

Phosphorus loads from agricultural non-point source pollution (NPSP) significantly degrade reservoir water quality, making adequate control of agricultural NPSP necessary for improving the water quality. Controlling NPSP is generally accomplished using various Best Management Practices (BMPs). The present study applies the Agricultural Non-Point Source Pollution (AGNPS) model to simulate NPSP loading and BMP efficiencies and establishes an enhanced multiobjective mixed-integer programming model for NPSP control strategy analyses based on these results. Cost, phosphorus load, sediment load and equity are the four major objectives considered. A case study for the Posan reservoir is presented. Four commonly proposed and applicable BMPs are chosen. Non-inferior solutions obtained using the constraint method and trade-off relationships among different control objectives are described and discussed. Compared with a previously proposed fertilizer control model, results show that the model established herein is more cost-effective and achieves better phosphorus and sediment loading reduction and equity goals. Furthermore, the current model is expected to facilitate decision-making analysis for development of an appropriate cost-sharing program to encourage adoption of appropriate BMPs by farmers.

The effect of glutamine-supplemented total parenteral nutrition on nitrogen economy depends on severity of diseases in surgical patients.

BACKGROUND: Gln is an important substrate for enterocyte and rapid proliferation cells. Studies have shown that parenteral supplementation of Gln maintains the intracellular Gln pool, improves nitrogen balance and shortens hospital stay. However, some studies showed Gln-supplemented TPN had no effect on restoring the Gln pool in critically ill patients. OBJECTIVE: To evaluate the effect of glutamine (Gln) dipeptide supplementation of total parenteral nutrition (TPN) on postoperative nitrogen balance and immune response of patients undergoing surgery. METHODS: This study is a prospective, randomized double-blind clinical trial. APACHE II score and TISS were used to evaluate the patients after admission. Forty-eight patients with major abdominal surgery were allocated to two groups to receive isonitrogenous (0.228 g nitrogen/kg/day) and isoenergetic (30 kcal/kg/day) TPN for 6 days. Two groups (Conv and Ala-Gln) were further divided to high (APACHE>or=6) and low (APACHE <6) groups. Control group (Conv) received 1.5 g amino acids/kg/day, whereas the Ala-Gln group received 0.972 g amino acids/kg/day and 0.417 g of L-alanyl-L-glutamine (Ala-Gln)/kg/day. Blood samples were collected on day 1 and day 6 after surgery for plasma amino acid and CD4, CD8 cell and T lymphocyte analysis. Cumulative nitrogen balance were also measured on day 2, 3, 4, 5 postoperatively. RESULTS: Although there was a tendency to have better cumulative nitrogen balance on the postoperative days in the Ala-Gln group, no significant difference was observed between two groups. However, a better significant cumulative nitrogen balance was observed on the 2nd, 3rd and 5th postoperative day in the Ala-Gln group than in the Conv group in patients with APACHE II <6, whereas no significant difference was noted in patients with APACHE II >or= 6. No difference in urine 3-methylhistidine excretion were observed between the 2 groups. Patients in the Ala-Gln group had significant higher T lymphocyte and CD4 cells than did those in the Conv group. CONCLUSION: TPN supplemented with Gln dipeptide had beneficial effect on enhancing the immune response. However, the effect of Ala-Gln administration on improving nitrogen economy was only observed in patients with low APACHE II scores. These results may indicate that Gln required for reversing the catabolic condition may depend on the characteristics and severity of the diseases.

Effects of glutamine-supplemented total parenteral nutrition on cytokine production and T cell population in septic rats.

BACKGROUND: This study was designed to investigate the effects of total parenteral nutrition (TPN) enriched with glutamine (GLN) on in vivo cytokine production and cellular immune response in early and late septic stages of rats. METHODS: Male Wistar rats were divided into 2 experimental groups and received TPN solution at an energy level of 270 kcal/kg body weight. The TPN solutions were isonitrogenous and identical in nutrients composition except for differences in amino acid content. One group received 2% GLN, whereas the other group received glycine (Gly) instead. TPN was maintained for 5 or 6 days according to the sacrifice schedule of the rats. On day 5, sepsis was induced by cecal ligation and puncture (CLP). Respective groups of rats were sacrificed 2, 4, 6, and 24 hours after CLP. RESULTS: Sepsis resulted in a negative nitrogen balance in both groups, and nitrogen loss was significantly lower in the GLN than the Gly group. Interleukin (IL)-2 and interferon (IFN)-gamma in most of the samples collected at various time points were not detectable in plasma or peritoneal lavage fluid. No differences in plasma IL-6 and TNF-alpha concentrations were observed between the GLN and Gly groups. Also, there were no significant differences in IL-1beta, IL-6, and TNF-alpha concentrations in peritoneal lavage fluid between the 2 groups at various time points. The CD4+/CD8+ ratio was significantly higher in the GLN group than in the Gly group only at 4 hours after CLP, and no difference was observed at 24 hours after CLP. CONCLUSIONS: TPN preinfused with a GLN-supplemented solution had a beneficial effect in ameliorating the extent of negative nitrogen balance in septic rats. However, parenterally administered GLN did not reduce the production of inflammatory mediators systemically or at the site of injury, and the influence on enhancing cellular immunity was not obvious.

Acute melatonin and para-chloroamphetamine interactions on pineal, brain and serum serotonin levels as well as stress hormone levels.

para-Chloroamphetamine, an amphetamine analog, alters serotonergic neurochemistry. In previous reports, melatonin (MEL), when administered with other amphetamine analogs, altered the decline in serotonin content produced by these analogs. The present studies assessed the effects of various doses of melatonin and p-chloroamphetamine on serotonin levels in numerous brain regions in male rats. Melatonin (10, 25 or 50 mg/kg, s.c.) and p-chloroamphetamine (3 or 5 mg/kg, s.c.) were administered and, 3 h later, brain samples and serum were collected. Serotonin levels in the serum and various regions of the brain were assayed using high-performance liquid chromatography. Melatonin in combination with a high dose of p-chloroamphetamine (5 mg/kg) produced cumulative deficits in serotonin levels in the serum. However, serotonin levels in the pineal, cortex or brain stem in all combined melatonin and p-chloroamphetamine groups were not significantly different from groups that received p-chloroamphetamine alone. Serum adrenocorticotropin (ACTH) and corticosterone levels were significantly elevated in the melatonin and p-chloroamphetamine combined groups, suggesting that animals receiving both treatments were more stressed than control animals or animals receiving melatonin or p-chloroamphetamine alone. These results indicate that melatonin does not alter p-chloroamphetamine-induced deficits in central serotonin levels. The increased serum adrenocorticotropic hormone, corticosterone and serotonin levels observed following melatonin and p-chloroamphetamine treatment suggest that this combination may have adverse peripheral effects.

Zinc supplementation does not attenuate alcohol-induced cerebellar Purkinje cell loss during the brain growth spurt period.

BACKGROUND: Alcohol-induced zinc deficiency is one of the mechanisms proposed as a cause of developmental brain damage associated with fetal alcohol syndrome. It is known that alcohol exposure during the brain growth spurt period leads to cerebellar Purkinje cell loss. Therefore, this study examined whether zinc supplementation was capable of preventing alcohol-induced Purkinje cell loss in the cerebellar vermis in a neonatal rat model system. METHODS: Sprague-Dawley rat pups were given alcohol (EtOH; 4.5 g/kg/day), zinc (Zn; 0.54 mg/ml diet; [10 times the regular diet Zn concentration]), or both from postnatal days (PD) 4 through 9 using the artificial-rearing paradigm. A gastrostomy control (GC) and a suckle control group (SC) also were included. All pups were killed on PD 10. Following perfusion, the cerebellar vermis was dissected and processed for stereological cell counting. The total number of Purkinje cells and the volume of the cerebellar vermis were determined. RESULTS: Alcohol produced a significant loss of Purkinje cells compared with that in the GC group (no EtOH and no Zn supplement). The zinc supplementation had no effect in attenuating alcohol-induced Purkinje cell loss in the cerebellar vermis. In fact, the serum zinc concentration data indicated higher zinc concentrations following either EtOH or Zn treatment. Interestingly, the GC group showed a significantly lower zinc concentration compared with the SC group, even though no significant difference in Purkinje cell numbers was observed between these two control groups. CONCLUSION: These findings indicate that alcohol exposure during the third trimester equivalent did not result in zinc deficiency in this neonatal rat model system, nor did zinc supplementation rescue the alcohol-induced Purkinje cell loss in the cerebellar vermis. These findings showed clearly that the serum zinc concentration was not correlated with Purkinje cell loss, suggesting that alcohol-induced loss of cerebellar Purkinje cells in this neonatal rat model system is independent of the availability of serum zinc.

Effects of parenteral infusion with fish-oil or safflower-oil emulsion on hepatic lipids, plasma amino acids, and inflammatory mediators in septic rats.

This study was designed to investigate the effects of preinfusion with total parenteral nutrition (TPN) using fish-oil (FO) versus safflower-oil (SO) emulsion as fat sources on hepatic lipids, plasma amino-acid profiles, and inflammatory-related mediators in septic rats. Normal rats, with internal jugular catheters, were assigned to two different groups and received TPN. TPN provided 300 kcal. kg(-1). d(-1), with 40% of the non-protein energy as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fat emulsion, which was made of SO or FO. After receiving TPN for 6 d, each group of rats was further divided into control and sepsis subgroups. Sepsis was induced by cecal ligation and puncture; control rats received sham operation. All rats were classified into four groups as follows: FO control group (FOC; n = 7), FO sepsis group (FOS; n = 8), SO control group (SOC; n = 8), and SO sepsis group (SOS; n = 9). The results of the study demonstrated that plasma concentrations of triacylglycerol and non-esterified fatty acids did not differ between the FO and SO groups, regardless of whether the animals were septic. SOS had significantly higher total lipids and cholesterol content in the liver than did the SOC group. The FOS group, however, showed no difference from the FOC group. Plasma leucine and isoleucine levels were significantly lower in the SOS group than in the SOC group, whereas no difference in these two amino acids was observed between the FOC and FOS groups. Plasma arginine levels were significantly lower in both septic groups than in the groups without sepsis when either FO or SO was infused. Plasma glutamine levels, however, did not differ across groups. No differences in interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, or leukotriene B(4) concentrations in peritoneal lavage fluid were observed between the two septic groups. These results suggest that catabolic reaction in septic rats preinfused with FO is not as obvious as those preinfused with SO. Compared with SO emulsion, TPN with FO emulsion prevents liver fat accumulation associated with sepsis. However, parenterally administered FO had no beneficial effect in lowering cytokines and LTB(4) levels in peritoneal lavage fluid in septic rats induced by cecal ligation and puncture.

Use of constitutive G protein-coupled receptor activity for drug discovery.

This article describes the behavior of transiently transfected human receptors into melanophores and the potential use of constitutive receptor activity to screen for new drug entities. Specifically, transient transfection of melanophores with different concentrations of receptor cDNA presumably leads to increased levels of receptor expression. This leads to an increased response to agonists (both maxima and potency) and, in some cases, an agonist-independent constitutive receptor activity. Transfections with increasing concentrations of the G(s) protein-coupled human calcitonin receptor type 2 (hCTR2) cDNA produced sufficient levels of constitutively activated receptor to cause elevated basal cellular responses. This was observed as a decrease in the transmittance of light through melanophores (consistent with G(s) protein activation) and increased response to human calcitonin. The receptor-mediated nature of this response was confirmed by its reversal with the hCTR2 peptide inverse agonist AC512. A collection of ligands for hCTR2 either increased or decreased constitutive hCTR2 activity, suggesting that the constitutive system was a sensitive discriminator of positive and negative ligand efficacy. Similar results were obtained with G(i)-protein-coupled receptors. Transient transfection of NPY1, NPY2, NPY4, CXCR4, and CCR5 cDNA produced increased light transmittance through melanophores (consistent with G(i)-protein activation). NPY1 cDNA produced little constitutive response on transfection, whereas maximal levels of constitutive activity ranging from 30 to 45% were observed for the other G(i)-protein-coupled receptors. Responses to agonists for these receptors increased (both maxima and potency) with increasing cDNA transfection. The receptor/G(i)-protein nature of both the constitutive and agonist-mediated responses was confirmed by elimination with pertussis toxin pretreatment. These data are discussed in terms of the theoretical aspects of constitutive receptor activity and the applicability of this approach for the general screening of G protein-coupled orphan receptors.

Constitutive receptor systems for drug discovery.

This paper discusses the use of constitutively active G-protein-coupled receptor systems for drug discovery. Specifically, the ternary complex model is used to define the two major theoretical advantages of constitutive receptor screening-namely, the ability to detect antagonists as well as agonists directly and the fact that constitutive systems are more sensitive to agonists. In experimental studies, transient transfection of Chinese hamster ovary cyclic AMP response element (CRE) luciferase reporter cells with cDNA for human parathyroid hormone receptor, glucagon receptor, and glucagon-like peptide (GLP-1) receptor showed cDNA concentration-dependent constitutive activity with parathyroid hormone (PTH-1) and glucagon. In contrast, no constitutive activity was observed for GLP-1 receptor, yet responses to GLP-1 indicated that receptor expression had taken place. In another functional system, Xenopus laevi melanophores transfected with cDNA for human calcitonin receptor showed constitutive activity. Nine ligands for the calcitonin receptor either increased or decreased constitutive activity in this assay. The sensitivity of the system to human calcitonin increased with increasing constitutive activity. These data indicate that, for those receptors which naturally produce constitutive activity, screening in this mode could be advantageous over other methods.

Effects of soybean oil and fish oil emulsions on glucose and lipid metabolism in streptozotocin-induced diabetic rats receiving total parenteral nutrition.

BACKGROUND: This study was designed to investigate the effects of fat emulsions with different fatty acid composition on plasma glucose and lipid metabolism in diabetic rats receiving total parenteral nutrition (TPN). METHODS: Diabetes was induced in rats with streptozotocin (STZ), and the rats were fed rat chow ad libitum for 6 weeks to achieve a chronic diabetic state. Control and diabetic rats were each divided into two TPN groups. The basal solutions of the two TPN groups were isonitrogenous and identical in nutrients composition except for the fat emulsion, which was made of soybean oil (SO) or fish oil (FO). The TPN control rats (C-SO and C-FO) and diabetic rats (DM-SO and DM-FO) received solutions with 37.5% of the non-protein energy provided as fat at an energy level of 30 kcal/100 g body wt/d. RESULTS: The results demonstrated that hyperglycemia and hypertriglyceridemia were induced by STZ in diabetic rats. There was no change in plasma glucose and insulin concentrations before and after TPN infusion in the TPN control groups, whereas plasma glucose as well as triglyceride (TG) and nonesterified fatty acid (NEFA) levels decreased significantly after TPN administration in the diabetic groups. No difference in the concentrations of plasma glucose, TGs, NEFAs, and insulin were observed between the two diabetic groups. CONCLUSIONS: These results suggest that compared with soybean oil, TPN with fish oil emulsion did not lead to lower plasma concentrations of TGs and NEFAs in STZ-induced diabetic rats. Also, no difference in plasma glucose and insulin levels between the two groups was observed.

Expression cloning and receptor pharmacology of human calcitonin receptors from MCF-7 cells and their relationship to amylin receptors.

Human breast cell carcinoma MCF-7 cells were found to bind 125I-labeled rat amylin (rAmylin) and the peptide amylin antagonist radioligand 125I-AC512 with high affinity. This high affinity binding possessed characteristics unique to the already defined high affinity binding site for amylin in the rat nucleus accumbens [Mol. Pharmacol. 44:493-497 (1993); J. Pharmacol. Exp. Ther. 270:779-787 (1994); Eur. J. Pharmacol. 262:133-141 (1994)]. To further define this receptor, we report results of expression cloning studies from an MCF-7 cell library. We isolated two variants of a seven-transmembrane receptor that were identical to two previously described human calcitonin receptors (hCTR1 and hCTR2). These receptors were characterized by expression in different surrogate host cell systems. Transient expression of hCTR1 in COS cells yielded membranes that bound 125I-AC512 and 125I-salmon calcitonin with high affinity, but no high affinity binding was observed with 125I-human calcitonin (hCAL) or 125I-rAmylin. Stable expression of hCTR1 in HEK 293 cells produced similar data. In contrast, expression of hCTR2 in COS cells yielded membranes that bound 125I-AC512, 125I-hCAL, and 125I-rAmylin with high affinity. The agonists 125I-hCAL and 125I-rAmylin bound 65% and 1.5%, respectively, of the sites bound by the antagonist radioligand 125I-AC512 in this expression system. This pattern of binding was repeated in HEK 293 cells stably transfected with hCTR2 (125I-hCAL = 24.8% Bmax, 125I-rAmylin = 8% Bmax). In both expression systems, the agonists hCAL and rAmylin were much more potent in displacing their radioligand counterparts than was the antagonist radioligand 125I-AC512. For example, the pKi value for displacement of 125I-AC512 by rAmylin was 7.2 in HEK 293 cells but rose to 9.1 when displacing 125I-rAmylin. Finally, hCTR2 was expressed in baculovirus-infected Ti ni cells. In this system, only specific binding to the antagonist 125I-AC512 and agonist 125I-hCAL was observed; no binding to 125I-rAmylin could be detected. These data are discussed in terms of two working hypotheses. The first is that amylin is a weak agonist for hCTR2 and that this receptor is unrelated to the amylin receptor found in this cell line. The second is that hCTR2 couples to different G proteins for calcitonin and amylin function in different cells. At present, these data cannot be used to disprove conclusively either hypothesis.

Angiotensinogen and angiotensin-I converting enzyme gene polymorphisms and the risk of coronary artery disease in Chinese.

The homozygous deletion allele (DD) of the angiotensin-I converting enzyme (ACE) gene and the T235 homozygote of the angiotensinogen (AGT) gene have been reported to be correlated with an increased prevalence of coronary artery disease (CAD) and myocardial infarction (MI). The importance of the DD genotype and T235 homozygote as genetic risk factors for CAD in Chinese remains uncertain. This study included 426 patients who underwent coronary angiography and 180 healthy subjects without clinical evidence of CAD. Coronary angiography identified 268 patients with CAD (CAD group) and 158 patients without CAD. The healthy subjects and patients without angiographic evidence of CAD constituted the control group. Three polymorphisms were studied: an insertion/deletion (I/D) polymorphism of the ACE gene and the T174 M and M235T polymorphisms of the AGT gene. No association was found between any of the three studied polymorphisms and the risk of CAD or MI in Chinese using univariate or multivariate analysis. In multivariate analysis, the relative risks were 1.20 (95% confidence interval = 0.91-1.61, P = 0.20) for the DD genotype, 1.05 (95% CI = 0.82-1.35, P = 0.69) for the T174 homozygote, and 1.19 (95% CI = 0.91-1.55, P = 0.20) for the T235 homozygote. Similarly, no significant difference was found in the frequencies of the DD genotype and the T174 and T235 homozygotes between the control group, the CAD group, the non-MI group, and the MI group when analyzed according to sex, age, or degree of risk. Our data suggest that neither the DD genotype of the ACE I/D polymorphism nor the T174 and T235 homozygotes of the AGT gene confer significant risk for CAD or MI in Chinese.

Decrease in myocardial Na(+)-K(+)-ATPase activity and ouabain binding sites in hypercholesterolemic rabbits.

OBJECTIVES: The purpose of this study was to explore the effect of high dietary cholesterol on the lipid composition, Na(+)-K(+)-ATPase activity and ouabain receptor property of the myocardial sarcolemma. METHODS: Male New Zealand white rabbits were fed with standard chow or standard chow supplemented with 0.5% (w/w) cholesterol and 10% (w/w) coconut oil to induce hypercholesterolemia. After 8 weeks, the rabbits were sacrificed; a myocardial sarcolemma fraction was then prepared from the left ventricular myocardium and analyzed for lipid composition. Assay of Na(+)-K(+)-ATPase activity and 3H-ouabain binding studies were performed in the myocardial sarcolemma from the control and cholesterol-fed rabbits. RESULTS: The cholesterol content, but not the phospholipid content, of the sarcolemma was significantly greater in the cholesterol-fed group, thus, resulting in an increased cholesterol/phospholipid molar ratio in the cholesterol-fed group. In addition, a decrease in Na(+)-K(+)-ATPase activity was also found in this group. The decrease in Na(+)-K(+)-ATPase activity was selective, since the Mg(++)-ATPase and 5'-nucleotidase activities remained unchanged. In the 3H-ouabain binding study, a decrease in the number of maximum binding sites, but not the binding affinity, for 3H-ouabain was found in the cholesterol-fed group. CONCLUSIONS: High dietary cholesterol induces higher levels of cholesterol not only in the plasma, but also in the myocardial sarcolemma. These changes result in decreased myocardial Na(+)-K(+)-ATPase activity mediated by a reduction in the maximum number of binding sites for ouabain but not a change in binding affinity.

Effects of n-3 and n-6 fatty acids on plasma eicosanoids and liver antioxidant enzymes in rats receiving total parenteral nutrition.

The effect of total parenteral nutrition (TPN) enriched with n-3 or n-6 fatty acids on the concentration of plasma eicosanoids was evaluated in rats. Rats were divided into three groups: the control group (n = 6) was fed a chow diet and infused with saline only. Two experimental groups (n = 11, 13) received TPN solutions at an energy level of 30 kcal/100g body weight with 40% energy provided as fat. The experimental groups were maintained on TPN for a period of 7 d. The basal TPN solutions were isonitrogenous and identical in nutrient composition except for differences in lipid source. One experimental group received a safflower oil emulsion, whereas the other group received a fish oil emulsion. At the end of the experimental period, plasma 6-keto prostaglandin F1 alpha, thromboxane B2, bleeding time, lipid peroxidation products, and antioxidant enzymes of liver were analyzed. The results demonstrated that the fish oil group had lower 6-keto prostaglandin F1 alpha concentration than the safflower oil group. Also, plasma thromboxane B2 was the lowest in the fish oil group among the three groups. There was no difference in bleeding time among the groups. With regard to liver lipid peroxidation products, malondialdehyde concentration was not higher in the fish oil group, whereas superoxide dismutase and glutathione peroxidase activities were lower in the fish oil group compared with the control and safflower oil groups. The results suggest that TPN prepared with fish oil fat emulsion causes less accumulation of lipid peroxidation products in the liver of rats, and may be beneficial in preventing platelet aggregation.

Prenatal alcohol treatment attenuated postnatal cocaine-induced elevation of dopamine concentration in nucleus accumbens: a preliminary study.

Prenatal alcohol exposure has been shown to damage the developing central nervous system (CNS) in a variety of ways, including neuroanatomical anomalies, neurochemical imbalance, and neuropharmacological dysfunction. The present study investigated one of the functional aspects of dopaminergic system in neonatal rats exposed prenatally to a binge-like alcohol paradigm by measuring dopamine concentrations following a single postnatal cocaine challenge. Pregnant Sprague-Dawley rats were given daily intragastric intubations of 5.1 g/kg alcohol solution from embryonic day (E) 1 to 20. Pair-fed and ad lib-fed animals served as controls. On E33 (usually postnatal day 10), offspring from all groups were given injections (IP) of either 0, 20, or 40 mg/kg cocaine. Animals were sacrificed and the substantia nigra/ventral tegmental area (SN/VTA) and nucleus accumbens (NAc) were dissected for the determination of dopamine concentrations using HPLC. Basal dopamine levels (0 mg/kg cocaine group) did not alter as a function of prenatal alcohol treatment in either region. However, acute cocaine injection increased the dopamine content in NAc, but not in SN/VTA, in ad lib-fed animals, and this elevation in dopamine level was significantly attenuated by prenatal alcohol treatment in both female and male animals, and by prenatal pair-fed treatment in male animals. Taken together, these results indicate that there appears to be a regional difference in acute cocaine-induced dopamine elevation, and prenatal binge-like alcohol exposure significantly alters the functional responsiveness of dopaminergic system in NAc. Furthermore, these data suggest that male offspring may be more sensitive to stress-associated or nutritional influences during gestation.

Pharmacological characterization and selectivity of the NPY antagonist GR231118 (1229U91) for different NPY receptors.

Neuropeptide Y (NPY) is widely distributed throughout the central and peripheral nervous system and exerts a wide range of physiological responses by activating specific receptors. In this study we have characterized the potency of the high affinity peptide dimer antagonist, GR231118, to displace radiolabeled NPY/PYY from different tissues and cell lines expressing Y1 or Y2 receptors and from CHO cells stably transfected with human cDNA encoding for Y1, Y2 and Y4 receptors. GR231118 displays high affinity for Y1 and Y4 receptors, equal or better than that of NPY itself, while its activity is several fold weaker for Y2 receptors. Displacement of radiolabeled PYY from rat hypothalamic membranes by GR231118, reveals the existence of high and low affinity binding sites which may be equated to Y1 and Y2 receptors respectively suggesting that the compound maybe used as a tool to dissect central NPY receptors.