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21.
Modulation of collagen production by fibroblasts. Effects of chronic exposure to agonists that increase intracellular cyclic AMP. 总被引:3,自引:0,他引:3 下载免费PDF全文
Cultured human lung fibroblasts were evaluated for their responsiveness to isoprenaline (isoproterenol) or prostaglandin E2 before and after chronic incubation with the agonist. Cells incubated for 6 h with either agonist were suppressed in terms of collagen production and exhibited increased intracellular cyclic AMP. Cells incubated for 72 h with the agonist and then re-challenged for 6 h with the same agonist did not demonstrate suppressed collagen production or increased cyclic AMP. Cells incubated for 72 h with isoprenaline still responded to prostaglandin E2 when challenged for 6 h; however, when the order of agonist exposure was reversed, cells incubated with prostaglandin E2 did not respond to a challenge by isoprenaline. If cells were allowed to recover for 48 h without the agonist after a 72 h chronic incubation, they recovered their responsiveness to the agonist. The results indicate that, although cultured fibroblasts may become desensitized to one agonist, they may retain their sensitivity to a second agonist and chronic suppression of collagen production may be achieved by alternate exposure to isoprenaline and prostaglandin E2. 相似文献
22.
Olympe Chazara Chi-Sheng Chang Nicolas Bruneau Khalid Benabdeljelil Jean-Claude Fotsa Boniface B. Kayang N’Goran E. Loukou Richard Osei-Amponsah Valentine Yapi-Gnaore Issaka A. K. Youssao Chih-Feng Chen Marie-Hélène Pinard-van der Laan Michèle Tixier-Boichard Bertrand Bed’Hom 《Immunogenetics》2013,65(6):447-459
The chicken major histocompatibility complex (MHC) is located on the microchromosome 16 and is described as the most variable region in the genome. The genes of the MHC play a central role in the immune system. Particularly, genes encoding proteins involved in the antigen presentation to T cells. Therefore, describing the genetic polymorphism of this region is crucial in understanding host–pathogen interactions. The tandem repeat LEI0258 is located within the core area of the B region of the chicken MHC (MHC-B region) and its genotypes correlate with serology. This marker was used to provide a picture of the worldwide diversity of the chicken MHC-B region and to categorize chicken MHC haplotypes. More than 1,600 animals from 80 different populations or lines of chickens from Africa, Asia, and Europe, including wild fowl species, were genotyped at the LEI0258 locus. Fifty novel alleles were described after sequencing. The resulting 79 alleles were classified into 12 clusters, based on the SNPs and indels found within the sequences flanking the repeats. Furthermore, hypotheses were formulated on the evolutionary dynamics of the region. This study constitutes the largest variability report for the chicken MHC and establishes a framework for future diversity or association studies. 相似文献
23.
S Chen AJ de Craen Y Raz E Derhovanessian AC Vossen WG Rudi G Pawelec AB Maier 《Immunity & ageing : I & A》2012,9(1):18-7
ABSTRACT: BACKGROUND: Cytomegalovirus (CMV) infection has been reported to contribute to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, CMV infection has not been evaluated as a possible risk factor for type 2 diabetes. Our aim was to investigate potential associations between CMV seropositivity, CMV IgG antibody level and glucose regulation in the oldest old. RESULTS: CMV seropositive subjects were more likely to have type 2 diabetes (17.2% vs 7.9%, p = 0.016), had a higher level of HbA1c (p = 0.014) and higher non-fasting glucose (p = 0.024) in the oldest olds. These associations remained significant after adjustment for possible confounders. CMV IgG antibody level was not significantly associated with glucose regulation (all p > 0.05). CONCLUSIONS: In the oldest old, CMV seropositivity is significantly associated with various indicators of glucose regulation. This finding suggests that CMV infection might be a risk factor for the development of type 2 diabetes in the elderly. 相似文献
24.
Hom JR Quintanilla RA Hoffman DL de Mesy Bentley KL Molkentin JD Sheu SS Porter GA 《Developmental cell》2011,21(3):469-478
Although mature myocytes rely on mitochondria as the primary source of energy, the role of mitochondria in the developing heart is not well known. Here, we find that closure of the mitochondrial permeability transition pore (mPTP) drives maturation of mitochondrial structure and function and myocyte differentiation. Cardiomyocytes at embryonic day (E) 9.5, when compared to E13.5, displayed fragmented mitochondria with few cristae, a less-polarized mitochondrial membrane potential, higher reactive oxygen species (ROS) levels, and an open mPTP. Pharmacologic and genetic closing of the mPTP yielded maturation of mitochondrial structure and function, lowered ROS, and increased myocyte differentiation (measured by counting Z bands). Furthermore, myocyte differentiation was inhibited and enhanced with oxidant and antioxidant treatment, respectively, suggesting that redox-signaling pathways lie downstream of mitochondria to regulate cardiac myocyte differentiation. 相似文献
25.
BACKGROUND: Quality is central to understanding provider motivations to join and remain within a social franchising network. Quality also appears as a key issue from the client's perspective, and may influence why a client chooses to use a franchised provider over another type of provider. The dynamic relationships between providers of social franchising clinics and clients who use these services have not been thoroughly investigated in the context of Myanmar, which has an established social franchising network. This study examines client motivations to use a Sun Quality Health network provider and provider motivations to join and remain in the Sun Quality Health network. Taken together, these two aims provide an opportunity to explore the symbiotic relationship between client satisfaction and provider incentives to increase the utilization of reproductive health care services. METHODS AND FINDINGS: Results from a series of focus group discussions with clients of reproductive health services and franchised providers shows that women chose health services provided by franchised private sector general practitioners because of its perceived higher quality, associated with the availability of effective, affordable, drugs. A key finding of the study is associated with providers. Provider focus group discussions indicate that a principle determinate for joining and remaining in the Sun Quality Health Network was serving the poor. 相似文献
26.
JK Hom B Wang S Chetty J Giddy M Mazibuko J Allen RP Walensky E Losina KA Freedberg IV Bassett 《PloS one》2012,7(8):e43281
Objective
To estimate the prevalence of drug-resistant tuberculosis (TB) and describe the resistance patterns in patients commencing antiretroviral therapy (ART) in an HIV clinic in Durban, South Africa.Design
Cross-sectional cohort study.Methods
Consecutive HIV-infected adults (≥18y/o) initiating HIV care were enrolled from May 2007–May 2008, regardless of signs or symptoms of active TB. Prior TB history and current TB treatment status were self-reported. Subjects expectorated sputum for culture (MGIT liquid and 7H11 solid medium). Positive cultures were tested for susceptibility to first- and second-line anti-tuberculous drugs. The prevalence of drug-resistant TB, stratified by prior TB history and current TB treatment status, was assessed.Results
1,035 subjects had complete culture results. Median CD4 count was 92/µl (IQR 42–150/µl). 267 subjects (26%) reported a prior history of TB and 210 (20%) were receiving TB treatment at enrollment; 191 (18%) subjects had positive sputum cultures, among whom the estimated prevalence of resistance to any antituberculous drug was 7.4% (95% CI 4.0–12.4). Among those with prior TB, the prevalence of resistance was 15.4% (95% CI 5.9–30.5) compared to 5.2% (95% CI 2.1–8.9) among those with no prior TB. 5.1% (95% CI 2.4–9.5) had rifampin or rifampin plus INH resistance.Conclusions
The prevalence of TB resistance to at least one drug was 7.4% among adults with positive TB cultures initiating ART in Durban, South Africa, with 5.1% having rifampin or rifampin plus INH resistance. Improved tools for diagnosing TB and drug resistance are urgently needed in areas of high HIV/TB prevalence. 相似文献27.
A N Van Hoek L H Luthjens M L Hom C H Van Os J A Dempster 《Biochemical and biophysical research communications》1992,184(3):1331-1338
The functional unit size of the water channel in rabbit erythrocytes was assessed using target size analysis following radiation inactivation. Using Radiochromic nylon dosimetry, accurate values of accumulated dose yielded an absolute target analysis, leading to direct determination of molecular size. The erythrocyte water channel functional size was shown to be 30 kDa, and is identical to the size found in rat renal proximal tubule brush border membranes (1), suggesting close homology of these two water channels. The result suggests that the 28 kDa channel-like intrinsic protein (CHIP28) recently isolated from human erythrocytes and proximal tubule (2), which is believed to form water channels of oligomeric construction may have a functional water channel activity in monomeric form. 相似文献
28.
T L Shih M R Candelore M A Cascieri S H Chiu L F Colwell L Deng W P Feeney M J Forrest G J Hom D E MacIntyre R R Miller R A Stearns C D Strader L Tota M J Wyvratt M H Fisher A E Weber 《Bioorganic & medicinal chemistry letters》1999,9(9):1251-1254
L-770,644 (9c) is a potent and selective agonist of the human beta3 adrenergic receptor (EC50 = 13 nM). It shows good oral bioavailability in both dogs and rats (%F = 27), and is a full agonist for glycerolemia in the rhesus monkey (ED50 = 0.21 mg/kg). Based on its desirable in vitro and in vivo properties, L-770,644 was chosen for further preclinical evaluation. 相似文献
29.
Ian K. Blaby Crysten E. Blaby-Haas Nicolas Tourasse Erik F.Y. Hom David Lopez Munevver Aksoy Arthur Grossman James Umen Susan Dutcher Mary Porter Stephen King George B. Witman Mario Stanke Elizabeth H. Harris David Goodstein Jane Grimwood Jeremy Schmutz Olivier Vallon Simon Prochnik 《Trends in plant science》2014,19(10):672-680
30.
AB Chang NC Cox J Purcell JM Marchant PJ Lewindon GJ Cleghorn LC Ee GD Withers MK Patrick J Faoagali 《Respiratory research》2005,6(1):1-5