|
Physiological, pharmacological, and nutritional regulation of circulating adiponectin concentrations |
|
|
|
Written by Administrator
|
|
Sunday, 01 June 2008 |
|
Physiological, pharmacological, and nutritional regulation of circulating adiponectin concentrations in humans Metab Syndr Relat Disord. 2008;6(2):87-102
Authors: Swarbrick MM, Havel PJ
Abstract Adiponectin is an adipocyte hormone that links visceral adiposity with insulin resistance and atherosclerosis. It is unique among adipocyte-derived hormones in that its circulating concentrations are inversely proportional to adiposity, and low adiponectin concentrations predict the development of type 2 diabetes and cardiovascular disease. Consequently, in the decade since its discovery, adiponectin has generated immense interest as a potential therapeutic target for the metabolic syndrome and diabetes. This review summarizes current research regarding the regulation of circulating adiponectin concentrations by physiological, pharmacological, and nutritional factors, with an emphasis on human studies. In humans, plasma adiponectin concentrations are influenced by age and gender, and are inversely proportional to visceral adiposity. In vitro studies suggest that adiponectin production may be determined primarily by adipocyte size and insulin sensitivity, with larger, insulin-resistant adipocytes producing less adiponectin. While adiponectin concentrations are unchanged after meal ingestion, they are increased by significant weight loss, such as after bariatric surgery. In addition, adiponectin production is inhibited by a number of hormones, including testosterone, prolactin, glucocorticoids and growth hormone, and by inflammation and oxidative stress in adipose tissue. Smoking decreases, while moderate alcohol consumption increases, circulating adiponectin concentrations. Dietary fatty acid composition in rodents influences adiponectin production via ligand-activated nuclear receptors (PPARs); however, current evidence in humans is equivocal. In addition to PPAR agonists (such as thiazolidinediones and fibrates), a number of pharmacological agents (angiotensin receptor type 1 blockers, ACE inhibitors, and cannabinoid receptor antagonists) used in treatment of the metabolic syndrome also increase adiponectin concentrations in humans.
PMID: 18510434 [PubMed - in process] |
|
|
Two thermostable nucleases coexisted in Staphylococcus aureus: evidence from mutagenesis |
|
|
|
Written by Administrator
|
|
Sunday, 01 June 2008 |
FEMS Microbiol Lett. 2008 May 26;
Authors: Tang J, Zhou R, Shi X, Kang M, Wang H, Chen H
Thermostable nuclease is known to be an important pathogenic factor unique to Staphylococcus aureus and it is commonly presumed to have had the same genetic origin. However, two ORFs in S. aureus genomes were predicted to encode nucleases. One encoded an unnamed nuclease A (SNase) (termed nuc1), and the other encoded a thermonuclease (TNase) named nuc (termed nuc2). In order to verify whether the two thermostable nuclease proteins are coexpressed in S. aureus, the nuc1 and nuc2 genes were cloned and expressed in Escherichia coli, and both of the recombinant proteins showed thermostable nuclease activity in a toluidine blue-DNA assay. Furthermore, a nuc1-deleted mutant of S. aureus strain RN4220 (termed RNDeltanuc1) was successfully constructed by homologous recombination. Selection and characterization of this mutant strain revealed that it still exhibited thermostable nuclease activity, but at a relative lower level than that of the parent strain. The nucleases secreted by the parent strain and nuc1-deleted strain still showed functional activity after 30 min at 121 degrees C. The findings indicated that two types of thermostable nucleases, encoded by two different genes, coexisted in S. aureus.
PMID: 18510563 [PubMed - as supplied by publisher] |
|
|
Pyramidal neurons in the septal and temporal CA1 field of the human and hedgehog tenrec hippocampus |
|
|
|
Written by Administrator
|
|
Sunday, 01 June 2008 |
Brain Res. 2008 Apr 26;
Authors: Liagkouras I, Michaloudi H, Batzios C, Psaroulis D, Georgiadis M, Künzle H, Papadopoulos GC
The present study examines comparatively the cellular density of disector-counted/Nissl-stained CA1 pyramidal neurons and the morphometric characteristics (dendritic number/length, spine number/density and Sholl-counted dendritic branch points/20 mum) of the basal and apical dendritic systems of Golgi-impregnated CA1 neurons, in the septal and temporal hippocampus of the human and hedgehog tenrec brain. The obtained results indicate that in both hippocampal parts the cellular density of the CA1 pyramidal neurons is lower in human than in tenrec. However, while the human pyramidal cell density is higher in the septal hippocampal part than in the temporal one, in the tenrec the density of these cells is higher in the temporal part. The dendritic tree of the CA1 pyramidal cells, more developed in the septal than in temporal hippocampus in both species studied, is in general more complex in the human hippocampus. The basal and the apical dendritic systems exhibit species related morphometric differences, while dendrites of different orders exhibit differences in their number and length, and in their spine density. Finally, in both species, as well as hippocampal parts and dendritic systems, changes of dendritic morphometric features along ascending dendritic orders fluctuate in a similar way, as do the number of dendritic branch points in relation to the distance from the neuron soma.
PMID: 18511020 [PubMed - as supplied by publisher] |
|
|
neuroprotective effects of NHE inhibitor in the gerbil hippocampal CA1 region |
|
|
|
Written by Administrator
|
|
Sunday, 01 June 2008 |
|
Late expression of Na(+)/H(+) exchanger 1 (NHE1) and neuroprotective effects of NHE inhibitor in the gerbil hippocampal CA1 region induced by transient ischemia. Exp Neurol. 2008 Apr 18;
Authors: Hwang IK, Yoo KY, An SJ, Li H, Lee CH, Choi JH, Lee JY, Lee BH, Kim YM, Kwon YG, Won MH
Although acidosis may be involved in neuronal death, the participation of Na(+)/H(+) exchanger (NHE) in delayed neuronal death in the hippocampal CA1 region induced by transient forebrain ischemia has not been well established. In the present study, we investigated the chronological alterations of NHE1 in the hippocampal CA1 region using a gerbil model after ischemia/reperfusion. In the sham-operated group, NHE1 immunoreactivity was weakly detected in the CA1 region. Two and 3 days after ischemia/reperfusion, NHE1 immunoreactivity was observed in glial components, not in neurons, in the CA1 region. Four days after ischemia/reperfusion, NHE1 immunoreactivity was markedly increased in CA1 pyramidal neurons as well as glial cells. These glial cells were identified as astrocytes based on double immunofluorescence staining. Western blot analysis also showed that NHE protein level in the CA1 region began to increase 2 days after ischemia/reperfusion. The treatment of 10 mg/kg 5-(N-ethyl-N-isopropyl) amiloride, a NHE inhibitor, significantly reduced the ischemia-induced hyperactivity 1day after ischemia/reperfusion. In addition, NHE inhibitor potently protected CA1 pyramidal neurons from ischemic damage, and NHE inhibitor attenuated the activation of astrocytes and microglia in the ischemic CA1 region. In addition, NHE inhibitor treatment blocked Na(+)/Ca(2+) exchanger 1 immunoreactivity in the CA1 region after transient forebrain ischemia. These results suggest that NHE1 may play a role in the delayed death, and the treatment with NHE inhibitor protects neurons from ischemic damage.
PMID: 18511042 [PubMed - as supplied by publisher] |
|
|
Immune responses of recombinant adenovirus co-expressing VP1 of foot-and-mouth disease virus |
|
|
|
Written by Administrator
|
|
Sunday, 01 June 2008 |
|
Immune responses of recombinant adenovirus co-expressing VP1 of foot-and-mouth disease virus and porcine interferon alpha in mice and guinea pigs. Vet Immunol Immunopathol. 2008 Apr 22;
Authors: Du Y, Dai J, Li Y, Li C, Qi J, Duan S, Jiang P
Foot-and-mouth disease (FMD) is a highly contagious and economically devastating vesicular disease of cloven-hoofed animals. In this study, we constructed and characterized the immune responses and vaccine efficacy conferred by the recombinant adenovirus co-expressing VP1 of FMDV and porcine interferon alpha as fusion protein (rAd-pIFNalpha-VP1). Six groups of female BALB/c mice each with 18 were inoculated subcutaneously twice 2-week intervals with the recombinant adenoviruses. The results showed that the levels of humoral and cell-mediated immune responses in the group inoculated with rAd-pIFNalpha-VP1 were significantly higher than those in the group inoculated with rAd-VP1+rAd-pIFNalpha (P<0.05). Then four groups of guinea pigs each with six were inoculated two times at 2-week intervals intramuscularly with rAd-pIFNalpha-VP1, commercial inactivated FMD vaccine, wild-type adenovirus (wtAd) or PBS, and the protective efficacy of rAd-pIFNalpha-VP1 was determined. The results indicated that all the guinea pigs vaccinated with rAd-pIFNalpha-VP1 as well as inactivated FMD vaccine were protected from FMDV challenge, even though the levels of neutralizing antibodies (1:32-1:40) of the animals vaccinated with rAd-pIFNalpha-VP1 was lower than that in the group inoculated with inactivated FMD vaccine (1:64-1:128). It demonstrated that the newly recombinant adenovirus rAd-pIFNalpha-VP1 might further be an attractive candidate vaccine for preventing FMDV infection in swine.
PMID: 18511133 [PubMed - as supplied by publisher] |
|
|
<< Start < Prev 11 12 13 14 15 16 17 18 19 Next > End >>
|
| Results 61 - 65 of 95 |