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排序方式: 共有403条查询结果,搜索用时 171 毫秒
101.
Mura A Anedda R Pintus F Casu M Padiglia A Floris G Medda R 《The FEBS journal》2007,274(10):2585-2595
The interaction of xenon with copper/6-hydroxydopa (2,4,5-trihydroxyphenethylamine) quinone (TPQ) amine oxidases from the plant pulses lentil (Lens esculenta) and pea (Pisum sativum) (seedlings), the perennial Mediterranean shrub Euphorbia characias (latex), and the mammals cattle (serum) and pigs (kidney), were investigated by NMR and optical spectroscopy of the aqueous solutions of the enzymes. (129)Xe chemical shift provided evidence of xenon binding to one or more cavities of all these enzymes, and optical spectroscopy showed that under 10 atm of xenon gas, and in the absence of a substrate, the plant enzyme cofactor (TPQ), is converted into its reduced semiquinolamine radical. The kinetic parameters of the analyzed plant amine oxidases showed that the k(c) value of the xenon-treated enzymes was reduced by 40%. Moreover, whereas the measured K(m) value for oxygen and for the aromatic monoamine benzylamine was shown to be unchanged, the K(m) value for the diamine putrescine increased remarkably after the addition of xenon. Under the same experimental conditions, the TPQ of bovine serum amine oxidase maintained its oxidized form, whereas in pig kidney, the reduced aminoquinol species was formed without the radical species. Moreover the k(c) value of the xenon-treated pig enzyme in the presence of both benzylamine and cadaverine was shown to be dramatically reduced. It is proposed that the lysine residue at the active site of amine oxidase could be involved both in the formation of the reduced TPQ and in controlling catalytic activity. 相似文献
102.
Raynner RD Barboza Wedson de MS Souto José da S Mourão 《Journal of ethnobiology and ethnomedicine》2007,3(1):1-14
Background
Viewed through the micro focus of an interpretive lens, medical anthropology remains mystified because interpretivist explanations seriously downplay the given context in which individual health seeking-behaviours occur. This paper draws upon both the interpretivist and political economy perspectives to reflect on the ethno medical practices within the Korean-Australian community in Sydney.Methods
We draw on research data collected between 1995 and 1997 for an earlier study of the use of biomedical and traditional medicine by Korean-Australians in Sydney. A total of 120 interviews were conducted with a range of participants, including biomedical doctors, traditional health professionals, Korean community leaders and Korean migrants representing a range of socio-economic backgrounds and migration patterns.Results and Discussion
First, the paper highlights the extent to which the social location of migrants in a host society alters or restructures their initial cultural practices they bring with them. Second, taking hanbang medicine in the Korean-Australian community as an illustrative case, the paper explores the transformation of the dominant biomedicine in Australia as a result of the influx of ethnomedicine in the era of global capitalism and global movement.Conclusion
In seeking to explain the popularity and supply of alternative health care, it is important to go beyond the culture of each kind of health care itself and to take into consideration the changes occurring at societal, national and global levels as well as consequential individual response to the changes. New social conditions influence the choice of health care methods, including herbal/alternative medicine, health foods and what are often called New Age therapies. 相似文献103.
Background
Adverse drug reactions (ADRs) are now recognized as an important cause of hospital admissions, with a proportion ranging from 0.9–7.9%. They also constitute a significant economic burden. We thus aimed at determining the prevalence and the economic burden of ADRs presenting to Medical Emergency Department (ED) of a tertiary referral center in India 相似文献104.
Plant copper/quinone amine oxidases are homodimeric enzymes containing Cu(II) and a quinone derivative of a tyrosyl residue (2,4,5-trihydroxyphenylalanine, TPQ) as cofactors. These enzymes catalyze the oxidative deamination of primary amines by a classical ping-pong mechanism, i.e. two distinct half-reactions, enzyme reduction by substrate followed by its re-oxidation by molecular oxygen. In the first half-reaction two forms of the reduced TPQ have been observed, the colorless Cu(II)-aminoquinol and the yellow Cu(I)-semiquinolamine radical so that this enzyme may be referred to as a "protein-radical enzyme". The interaction of xenon, in aqueous solutions, with the copper/TPQ amine oxidase from lentil (Lens esculenta) seedlings has been investigated by NMR and optical spectroscopy. NMR data indicate that xenon binds to the protein. Under 10 atm gaseous xenon and in the absence of substrates more than 60% native enzyme is converted into Cu(I)-semiquinolamine radical species, showing for the first time that both monomers in the dimer can generate the radical. Under the same experimental conditions the copper-free lentil enzyme is able to generate an intermediate absorbing at about 360 nm, which is assigned to the product Schiff base quinolaldimine which, to the best of our knowledge, has never been observed during the catalytic mechanism of plant amine oxidases. A possible role of the lysine residue responsible for the formation of Cu(I)-semiquinolamine and quinolaldimine, is proposed. 相似文献
105.
V. Carcangiu M.C. Mura G.M. Vacca M. Pazzola M.L. Dettori S. Luridiana P.P. Bini 《Animal reproduction science》2009,116(1-2):65-72
The aim was to study the polymorphisms of the melatonin receptor 1A gene (MTNR1A) and its relationship with seasonal reproduction in the Sarda sheep breed. Four-thousand multiparous ewes reared under natural photoperiod were randomly chosen. Genomic DNA was extracted and subjected to PCR for the amplification of the main part of exon II of the ovine MTNR1A gene (GenBank U14109). PCR products were subjected to restriction enzymes MnlI and RsaI and placed into +/+, +/− or −/− group for MnlI and C/C, C/T or T/T group for RsaI. Samples were cloned and sequenced. The sequences were aligned with the U14109 sequence of GenBank. Data were subjected to allelic frequency analysis and to the χ2 test in order to evaluate the link between genotype and reproductive activity. After MnlI digestion, allelic frequency was 0.78 for allele +and 0.22 for allele −; genotype frequency of the +/+ homozygote was 68%, 20.5% for +/− and 11.5% for −/−. After RsaI, allelic frequency was 0.66 for allele C and 0.34 for allele T; genotype frequency of the C/C homozygote was 53.5%, 26% for C/T and 20.5% for T/T. The population was in Hardy-Weinberg disequilibrium both for the MnlI and RsaI. Lambing frequency of +/+ genotype ewes was higher in the period September–December while for −/− genotype in January–April (P < 0.01). Lambing of C/C genotype ewes showed a higher frequency in September–December while for T/T genotype in January–April (P < 0.01). Results confirmed that the polymorphism of the MTNR1A locus was also present in the Sarda with a higher incidence of the +/+ and C/C genotypes. The animals that carried one of these two gene isoforms showed a not seasonal reproductive activity with the lambing period in September–December. 相似文献
106.
107.
108.
Kajsa Sjöholm Björn Carlsson Lena MS Carlsson 《Central European Journal of Biology》2006,1(2):221-234
The leptin system regulates body fat mass through a feedback loop between adipose tissue and the hypothalamus. To test if
leptin responsiveness may be regulated we assayed hypothalamic response to leptin during the estrous cycle; when changes in
food intake are known to occur. Immature rats were treated with pregnant mare’s serum gonadotropin (PMSG) to induce synchronized
follicular development, ovulation and corpus luteum formation. Leptin response was estimated by measuring the in vitro induction of tis11, a primary response gene activated by STAT3-dependent cytokines in hypothalamic explants after leptin stimulation. In addition,
mRNA levels of the suppressor cytokine signaling-3 (SOCS-3), a possible mediator of leptin resistance, were analyzed. Serum
leptin levels did not change between days 2 and day 3 (corresponding to proestrus and estrus, respectively) but the response
to leptin was higher on day 2 than on day 3 (p=0.05). Food intake displayed a tendency towards downregulation between day
1 and day 2 (p=0.057), and a tendency towards upregulation between day 2 and day 3 (p=0.072), although the body weight increased
on day of the study (p<0.0001). There was no significant difference in hypothalamic expression of SOCS-3 between day 2 and
day 3. In conclusion, we have shown that leptin responsiveness changes during a hormonally induced estrous cycle in rats.
Our data suggest that a change in the hypothalamic response to leptin may cause the cyclic feeding behavior seen in rats. 相似文献
109.
Gotsman M Dusa C Nassar H Hasin Y Lotan C Rozenman Y 《International journal of cardiovascular interventions》1999,2(3):187-190
The Cutting Balloon consists of a standard balloon dilatation catheter with four microtome-sharp blades that incise the plaque and minimize arterial wall trauma. It was used in 31 patients; nine had calcified arteries, ten had non-compliant lesions, three had in-stent restenosis and nine had aorto-ostial lesions. Seventeen lesions were predilated, 28 were post-dilated and 18 required stent implantation. The procedure was very effective in aorto-ostial lesions, non-compliant lesions that were not responsive to high-pressure balloon dilatation, and was partially successful in calcified arteries. It has a very specific niche in selected lesions. 相似文献
110.
Receptor usage and fetal expression of ovine endogenous betaretroviruses: implications for coevolution of endogenous and exogenous retroviruses
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Betaretroviruses of sheep include two exogenous viruses, Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV), and a group of endogenous viruses known as enJSRVs. The exogenous JSRV and ENTV are the etiological agents of ovine pulmonary adenocarcinoma (OPA) and enzootic nasal tumor (ENT), respectively. Sheep affected by OPA or ENT do not show an appreciable antibody response to JSRV or ENTV. Consequently, it is conceivable that enJSRV expression in the fetal lamb tolerizes sheep to the related exogenous viruses. In this study, possible mechanisms of interference between the sheep exogenous and endogenous betaretroviruses were investigated. In situ hybridization detected enJSRV RNAs in lymphoid cells associated with the lamina propria of the small intestine and in the thymus of sheep fetuses. Low-level expression of enJSRVs was also detected in the lungs. In addition, expression of enJSRVs was found to block entry of the exogenous JSRV, presumably via mechanisms of receptor interference. Indeed, enJSRVs, like JSRV and ENTV, were found to utilize hyaluronidase-2 as a cellular receptor. 相似文献