Effects of xiaoyu tablet on endothelin-1, nitric oxide, and apoptotic cells of atherosclerotic vessel wall in rabbits. (1/47)

AIM: To investigate the mechanism of xiaoyu tablet on reduction of smooth muscle cells (SMC) in atherosclerotic vessel wall. METHODS: The atherosclerotic model was performed in male New Zealand rabbits that were given high fat diet and abrasion of the abdominal aorta endothelial cells. The rabbits were then administered with xiaoyu tablet 0.16-0.32 g x kg(-1) x d(-1) for 16 weeks. Changes in morphology, endothelin (ET)-1, nitric oxide (NO), and apoptotic cells of atherosclerotic vessel wall were determined by the microscopy, radioimmunoassay, colorimetric method, the techniques of DNA in situ end labeling, and image pattern analysis, respectively. RESULTS: After 16 weeks of xiaoyu tablet treatment, intimal thickness and SMC in atherosclerotic vessel wall were diminished, ET-1 was decreased by 8.2 %-42.6 %, NO was increased by 7.5 %-54.2 %, and labeled apoptotic nuclei were markedly decreased, the area and integral optical density of positive granule were (846+/-308) microm2 and 3425+/-1374 in atherosclerotic group and (225+/-60) microm2 and 1445+/-606 in xiaoyu tablet 0.32 g/kg group, respectively. CONCLUSION: Xiaoyu tablet not only inhibited proliferation of SMC through reducing ET-1 in atherosclerotic vessel wall, but also induced apoptosis of SMC by increasing NO in vessel wall.  (+info)

Determination of flavones in Crataegus pinnatifida by capillary zone electrophoresis. (2/47)

A capillary electrophoretic method for the separation of four flavones in Crataegus pinnatifida is developed. The four flavones in Crataegus pinnatifida are separated on baseline within 15 min using 50mM borax buffer containing 15% acetonitrile and adjusted to pH 8.15 with phosphoric acid. The detection limits of vitexin-2"-rhamnoside, hyperside, rutin, and vitexin are 0.35, 0.30, 0.40 and, 0.29 microg/mL, respectively. The recovery of these flavones is as follows: vitexn-2"-rhamnoside 96.8%, hyperside 99.9%, rutin 97.1%, and vitexin 97.8%. The results are in accordance with those obtained in the high-performance liquid chromatography system. The content of flavones is higher in Crataegus pinnatifida leaves than in its fruits, and hyperside is not detected in either Crataegus pinnatifida fruits or flowers.  (+info)

The mathematical treatment of leaf venation: the variation in secondary vein length along the midrib. (3/47)

BACKGROUND AND AIMS: In some dicotyledonous leaves and leaflets, the secondary veins run more-or-less straight to the margins and have well-defined lengths. For a given half-lamina of length L, an equation, previously proposed, relates the lengths of these veins, p, to the distances, l, between the leaf tip and their insertions on the midrib: p = B2(x+y)l(x)(L - l)(y)/L(x+y-1), where B, x and y are fitted parameters. Aspects of the formula are re-examined, including its general applicability, significance and usefulness. METHODS: Length measurements were made on leaves of various dicotyledons, notably Ulmus glabra, U. procera, Alnus viridis, A. glutinosa, Corylus avellana and Crataegus monogyna. Equations were fitted by non-linear regression. KEY RESULTS: The equation has now been applied descriptively to 23 species of eight families, but it is sometimes preferable or necessary to replace the measured length, L, with a fourth parameter that may differ significantly from it. Within a given species, values of the indices x and y are positively correlated. Leaves of some U. glabra depart qualitatively from the general pattern. As an example of hypothesis testing, the equation was used to show that the retuse or emarginate leaf tips of A. glutinosa are not due to stunting. CONCLUSIONS; That the equation applies to many species suggests that the underlying processes of leaf growth are quantitatively similar. Although relevant knowledge of these is scant, consideration of mathematical relationships may help their elucidation.  (+info)

The procyanidin-induced pseudo laminar shear stress response: a new concept for the reversal of endothelial dysfunction. (4/47)

Reduced endothelium-dependent vasodilator responses with increased synthesis of ET-1 (endothelin-1) are characteristics of endothelial dysfunction in heart failure and are predictive of mortality. Identification of treatments that correct these abnormalities may have particular benefit for patients who become refractory to current regimens. Hawthorn preparations have a long history in the treatment of heart failure. Therefore we tested their inhibitory effects on ET-1 synthesis by cultured endothelial cells. These actions were compared with that of GSE (grape seed extract), as the vasoactive components of both these herbal remedies are mainly oligomeric flavan-3-ols called procyanidins. This showed extracts of hawthorn and grape seed were equipotent as inhibitors of ET-1 synthesis. GSE also produced a potent endothelium-dependent vasodilator response on preparations of isolated aorta. Suppression of ET-1 synthesis at the same time as induction of endothelium-dependent vasodilation is a similar response to that triggered by laminar shear stress. Based on these results and previous findings, we hypothesize that through their pharmacological properties procyanidins stimulate a pseudo laminar shear stress response in endothelial cells, which helps restore endothelial function and underlies the benefit from treatment with hawthorn extract in heart failure.  (+info)

Postzygotic isolating factor in sympatric speciation in Rhagoletis flies: reduced response of hybrids to parental host-fruit odors. (5/47)

Rhagoletis pomonella is a model for sympatric speciation (divergence without geographic isolation) by means of host-plant shifts. Many Rhagoletis species are known to use fruit odor as a key olfactory cue to distinguish among their respective host plants. Because Rhagoletis rendezvous on or near the unabscised fruit of their hosts to mate, behavioral preferences for fruit odor translate directly into premating reproductive isolation among flies. Here, we report that reciprocal F(1) hybrids between the apple and hawthorn host races of R. pomonella, as well as between the host races and an undescribed sibling species infesting Cornus florida (flowering dogwood) do not respond to host fruit volatiles in wind-tunnel assays at doses that elicit maximal directed flight in parental flies. The reduced ability of hybrids to orient to fruit volatiles could result from a conflict between neural pathways for preference and avoidance behaviors, and it suggests that hybrids might suffer a fitness disadvantage for finding fruit in nature. Therefore, host-specific mating may play a dual role as an important postzygotic as well as a premating reproductive barrier to isolate sympatric Rhagoletis flies.  (+info)

A peroxisome proliferator response elements regulatory system in xenopus oocytes and its application. (6/47)

BACKGROUND: Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a kind of ligand-activated transcription factors binding to peroxisome proliferator response element (PPRE), a specific recognition site. It is thought to play a critical role in glucose and lipid metabolism and in inflammation control. The aim of this study was to establish a new cellular model for the quick screening of lipid-lowering drugs, which may be effective as PPAR-gamma ligands on the PPRE-mediated pathway regulatory system. METHODS: Two plasmids were constructed: pXOE-PPARgamma, in which the human PPARgamma gene was in the downstream of TFIIIA gene promoter, and pLXRN-PPRE-d2EGFP, in which the enhanced green fluorescent protein (EGFP) gene was subcloned into PPRE. The xenopus oocytes were injected with these two plasmids, and consequently treated with prostaglandin E1, pioglitazone, and different kinds of lipid-lowering drugs. After 3 days, the oocytes were observed under a fluorescence microscope. To confirm the drug action,we injected pXOE-PPARgamma plasmid into the oocytes, which then treated with prostaglandin E1 and Hawthorn flavonoids. The mass of expressed lipoprotein lipase (LPL) in the cells was determined by enzyme labeling linked immunosorbent assay (ELISA). RESULTS: The expression of EGFP was only induced by prostagalandin E1, pioglitazone, Hawthorn flavonoids. A concentration-response relationship was seen between expressed EGFP and Hawthorn flavonoids. The levels of LPL in both Hawthorn flavonoids groups and PPARgamma ligand prostagalandin E1 group injected with pXOE-PPARgamma plasmid increased significantly (< 0.001) compared with controls, and a concentration-response relationship was observed between LPL mass and Hawthorn flavonoids. CONCLUSIONS: It is possible to establish a PPRE regulatory EGFP reporter system in xenopus oocytes to monitor the activity of PPARgamma ligand. Hawthorn flavonoids can increase the expression of gene downsteam of PPRE by effect on the PPRE pathway regulatory system.  (+info)

Regulation of lipoprotein lipase expression by effect of hawthorn flavonoids on peroxisome proliferator response element pathway. (7/47)

To investigate the possibility that natural medicines affect lipid metabolism by regulating lipoprotein lipase (LPL) expression, a green fluorescent protein (GFP) gene was constructed downstream of the peroxisome proliferator response element (PPRE) and the constructed plasmid was microinjected into Xenopus oocytes to establish a PPRE regulatory reporter system. Using this system, hawthorn flavonoids were quickly selected from a panel of natural medicines and found to up-regulate GFP expression by an effect on PPRE. To confirm the effect of hawthorn flavonoids, we treated mice orally with water (control), hawthorn flavonoids, and pioglitazone and measured the LPL levels in serum, adipose tissue, and muscle by an enzyme-linked immunosorbent assay. The serum LPL levels were no different from the controls after treatment with either hawthorn flavonoids or pioglitazone, but LPL increased significantly in muscular tissues and decreased in adipose tissues. These results demonstrate that hawthorn flavonoids meditate LPL expression in mice with tissue-specific differences. A novel PPRE regulatory report system was established for rapid and effective selection and evaluation of LPL-mediating drugs.  (+info)

Colorectal cancer and CHF - reviewing the evidence for complementary medicine. (8/47)

This is the third of a series of articles looking at the available evidence for complementary medicine. Physical activity is important in attenuating harmful effects of aging and the onset of chronic disease. Benefits of physical activity in preventing or delaying cardiovascular disease and managing obesity and arthritis have mainstream acceptance. However, evidence is emerging of the benefits of physical activity in other conditions such as cancer.  (+info)