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101.
Pang J Salim A Lee VJ Hibberd ML Chia KS Leo YS Lye DC 《PLoS neglected tropical diseases》2012,6(5):e1641
Background
Dengue hemorrhagic fever (DHF) is a severe form of dengue, characterized by bleeding and plasma leakage. A number of DHF risk factors had been suggested. However, these risk factors may not be generalized to all populations and epidemics for screening and clinical management of patients at risk of developing DHF. This study explored demographic and comorbidity risk factors for DHF in adult dengue epidemics in Singapore in year 2006 (predominantly serotype 1) and in year 2007–2008 (predominantly serotype 2).Methods
A retrospective case-control study was conducted with 149 DHF and 326 dengue fever (DF) patients from year 2006, and 669 DHF and 1,141 DF patients from year 2007–2008. Demographic and reported comorbidity data were collected from patients previously. We performed multivariate logistic regression to assess the association between DHF and demographic and co-morbidities for year 2006 and year 2007–2008, respectively.Results
Only Chinese (adjusted odds ratio [AOR] = 1.90; 95% confidence interval [CI]: 1.01–3.56) was independently associated with DHF in year 2006. In contrast, age groups of 30–39 years (AOR = 1.41; 95% CI:1.09–1.81), 40–49 years (AOR = 1.34; 95% CI:1.09–1.81), female (AOR = 1.57; 95% CI:1.28–1.94), Chinese (AOR = 1.67; 95% CI:1.24–2.24), diabetes (AOR = 1.78; 95% CI:1.06–2.97), and diabetes with hypertension (AOR = 2.16; 95%CI:1.18–3.96) were independently associated with DHF in year 2007–2008. Hypertension was proposed to have effect modification on the risk of DHF outcome in dengue patients with diabetes. Chinese who had diabetes with hypertension had 2.1 (95% CI:1.07–4.12) times higher risk of DHF compared with Chinese who had no diabetes and no hypertension.Conclusions
Adult dengue patients in Singapore who were 30–49 years, Chinese, female, had diabetes or diabetes with hypertension were at greater risk of developing DHF during epidemic of predominantly serotype 2. These risk factors can be used to guide triaging of patients who require closer clinical monitoring and early hospitalization in Singapore, when confirmed in more studies. 相似文献102.
James AW Zara JN Corselli M Chiang M Yuan W Nguyen V Askarinam A Goyal R Siu RK Scott V Lee M Ting K Péault B Soo C 《Journal of visualized experiments : JoVE》2012,(63):e2952
Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering. PSCs are a FACS-sorted population of 'pericytes' (CD146+CD34-CD45-) and 'adventitial cells' (CD146-CD34+CD45-), each of which we have previously reported to have properties of mesenchymal stem cells. PSCs, like MSCs, are able to undergo osteogenic differentiation, as well as secrete pro-osteogenic cytokines. In the present protocol, we demonstrate the osteogenicity of PSCs in several animal models including a muscle pouch implantation in SCID (severe combined immunodeficient) mice, a SCID mouse calvarial defect and a femoral segmental defect (FSD) in athymic rats. The thigh muscle pouch model is used to assess ectopic bone formation. Calvarial defects are centered on the parietal bone and are standardly 4 mm in diameter (critically sized). FSDs are bicortical and are stabilized with a polyethylene bar and K-wires. The FSD described is also a critical size defect, which does not significantly heal on its own. In contrast, if stem cells or growth factors are added to the defect site, significant bone regeneration can be appreciated. The overall goal of PSC xenografting is to demonstrate the osteogenic capability of this cell type in both ectopic and orthotopic bone regeneration models. 相似文献
103.
Michael J. Selig Chia‐Wen Carmen Hsieh Lisbeth G. Thygesen Michael E. Himmel Claus Felby Stephen R. Decker 《Biotechnology progress》2012,28(6):1478-1490
Milliliter scale (ligno)cellulose saccharifications suggest general solute concentration and its impact on water availability plays a significant role in detrimental effects associated with high solids lignocellulose conversions. A microtumbler developed to enable free‐fall mixing at dry solids loadings up to 35% (w/w) repeatedly produced known detrimental conversion trends on cellulose, xylan and pretreated lignocellulose with commercial enzymes. Despite this, high concentrations of insoluble nonhydrolysable dextrans did not depress saccharification extents in 5% (w/w) cellulose slurries suggesting mass transfer limitations may not significantly limit hydrolysis extents at high solids loadings. Interestingly, cellulose saccharification by purified cellulases showed increased conversions with increasing dry solids loadings. This prompted investigations into impacts the concentration of soluble species, such as sugar alcohols, low molecular weight enzyme preparation components, and monomer hydrolysis products, have on the hydrolysis environment. Such substances significantly depress conversion rates and were shown to correlatively lower water activity (Aw) in the hydrolysis environment while high insoluble solids concentrations did not. Furthermore, low‐field NMR on concentrated slurries of insoluble complex carbohydrates, including the nonhydrolysable dextrans, showed all solids constrained water significantly more than high concentrations of soluble species (inhibitory) suggesting water constraint may not be as problematic an issue at high solids loadings compared to the availability of water in the system. Additionally, the introduction of soluble species lessened overall water constraint in high solids systems and appears to shift the distribution of water away from insoluble surfaces. This is potentially a critical issue for industrial processes operating at high dry solids levels. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012 相似文献
104.
Huynh TP Mah V Sampson VB Chia D Fishbein MC Horvath S Alavi M Wu DC Harper J Sarafian T Dubinett SM Langhans SA Goodglick L Rajasekaran AK 《American journal of physiology. Lung cellular and molecular physiology》2012,302(11):L1150-L1158
Diminished Na,K-ATPase expression has been reported in several carcinomas and has been linked to tumor progression. However, few studies have determined whether Na,K-ATPase function and expression are altered in lung malignancies. Because cigarette smoke (CS) is a major factor underlying lung carcinogenesis and progression, we investigated whether CS affects Na,K-ATPase activity and expression in lung cell lines. Cells exposed to CS in vitro showed a reduction of Na,K-ATPase activity. We detected the presence of reactive oxygen species (ROS) in cells exposed to CS before Na,K-ATPase inhibition, and neutralization of ROS restored Na,K-ATPase activity. We further determined whether Na,K-ATPase expression correlated with increasing grades of lung adenocarcinoma and survival of patients with smoking history. Immunohistochemical analysis of lung adenocarcinoma tissues revealed reduced Na,K-ATPase expression with increasing tumor grade. Using tissue microarray containing lung adenocarcinomas of patients with known smoking status, we found that high expression of Na,K-ATPase correlated with better survival. For the first time, these data demonstrate that CS is associated with loss of Na,K-ATPase function and expression in lung carcinogenesis, which might contribute to disease progression. 相似文献
105.
Vincent Ries Robert M. Silva Tinmarla F. Oo Hsiao‐Chun Cheng Margarita Rzhetskaya Nikolai Kholodilov Richard A. Flavell Chia‐Yi Kuan Pasko Rakic Robert E. Burke 《Journal of neurochemistry》2008,107(6):1578-1588
Activation of c‐jun N‐terminal kinase (JNK) by the mitogen‐activated protein kinase cascade has been shown to play an important role in the death of dopamine neurons of the substantia nigra, one of the principal neuronal populations affected in Parkinson’s disease. However, it has remained unknown whether the JNK2 and JNK3 isoforms, either singly or in combination, are essential for apoptotic death, and, if so, the mechanisms involved. In addition, it has been unclear whether they play a role in axonal degeneration of these neurons in disease models. To address these issues we have examined the effect of single and double jnk2 and jnk3 null mutations on apoptosis in a highly destructive neurotoxin model, that induced by intrastriatal 6‐hydroxydopamine. We find that homozygous jnk2/3 double null mutations result in a complete abrogation of apoptosis and a prolonged survival of the entire population of dopamine neurons. In spite of this complete protection at the cell soma level, there was no protection of axons. These studies provide a striking demonstration of the distinctiveness of the mechanisms that mediate cell soma and axon degeneration, and they illustrate the need to identify and target pathways of axon degeneration in the development of neuroprotective therapeutics. 相似文献
106.
Drosophila neuroblast asymmetric divisions: cell cycle regulators, asymmetric protein localization, and tumorigenesis 总被引:1,自引:0,他引:1
Over the past decade, many of the key components of the genetic machinery that regulate the asymmetric division of Drosophila melanogaster neural progenitors, neuroblasts, have been identified and their functions elucidated. Studies over the past two years have shown that many of these identified components act to regulate the self-renewal versus differentiation decision and appear to function as tumor suppressors during larval nervous system development. In this paper, we highlight the growing number of molecules that are normally considered to be key regulators of cell cycle events/progression that have recently been shown to impinge on the neuroblast asymmetric division machinery to control asymmetric protein localization and/or the decision to self-renew or differentiate. 相似文献
107.
DO-stat fed-batch production of 2-keto-d-gluconic acid from cassava using immobilized Pseudomonas aeruginosa 总被引:1,自引:0,他引:1
Bioconversion of cassava-derived glucose to 2-keto-d-gluconic acid (2-KDG) using resting cells of immobilized Pseudomonas aeruginosa IFO 3448 was investigated. The tuberous roots of cassava were selected as the feedstock as they are inexpensive and widely
available, and possess high amounts of starch (approximately 70% (w/w) of dry mass). Immobilized bacteria was used in a fed-batch fermenter and recycled over a period of 2 weeks. Given that the
formation of 2-KDG from glucose requires oxygen as a reagent, and that high glucose concentrations are detrimental to the
production yield of 2-KDG by resting cells, a DO-stat control strategy was used, whereby the feed rate of cassava hydrolysate
was regulated by coupling it with the control variable, dissolved oxygen. For 319 h of operation including three cycles of
repeated fed batch, 72 g of 2-KDG was produced from hydrolysate derived from 110 g of dried cassava at a maximum production
rate of 0.55 g/L/h and an average concentration of 35 g/L. 相似文献
108.
109.
Responses of virus-infected (VI) and virus-eradicated (VE) Oncidium Gower Ramsey orchid plants grown under 30% of prevailing solar radiation and those transferred from 30 to 60% and 100% of prevailing solar radiation were studied under natural tropical conditions. Plants grown under 30% of prevailing solar radiation suffered lower leaf and floral production and reduced photosynthesis. When the irradiance was increased to 60% of prevailing solar radiation, enhancement of leaf and floral production and photosynthetic capacities were achieved. However, when the plants were transferred from 30 to 100% of prevailing solar radiation, the growth and photosynthetic capacities of the plants were significantly reduced. All plants exhibited a midday depression in photosynthetic CO2 assimilation ( A ), stomatal conductance ( g s ) and F v / F m ratio . The degree of midday depression of these parameters was not only associated with high temperatures and high irradiances but also with virus infection. Midday F v / F m ratio depression indicated that dynamic photo-inhibition occurred in all plants grown under all three light conditions. However, chronic photo-inhibition, measured by pre-dawn F v / F m ratio and chlorophyll content, occurred only in those plants transferred from 30 to 100% of prevailing solar radiation. Hence, it is concluded that the VI Oncidium Gower Ramsey was more susceptible to high irradiance than the VE plants. 相似文献
110.
From 1997 to 1999Cycas debaoensis Y. C. Zhong & C. J. Chen andC. changjiangensis N. Liu were described from South China. The wild populations ofCycas szechuanensis were discovered in Fujian.Cycas guizhouensis K. M. Lan & R. F. Zou at the higher elevations andC. segmentifida D. Y. Wang & C. Y. Deng at the lower elevations along the Nanpanjiang River should be good species, which were treated by
Chen and Wang (1995) and Chen and Stevenson (1999) as synonyms forC. szechuanensis. However, 11 other new species have been reduced by Chen and Stevenson (1999) and the present authors. They areC. longlinensis Huang T. Chang & Y. C. Zhong,C. xilinensis Huang T. Chang & Y. C. Zhong, C.multifida Huang T. Chang & Y. C. Zhong, C.longiconifera Huang T. Chang & Y. C. Zhong, andC. acuminatissima Huang T. Chang & Y. C. Zhong, all treated as synonyms ofC. segmentifida. Cycas spiniformis J. Y. Liang,C. longisporophylla F. N. Wei,C. septermsperma Huang T. Chang & H. X. Zhang,C. brevipinnata Huang T. Chang et al. should be synonyms forC. exseminifera F. N. Wei.Cycas miquelii Warb, andEpicycas miquelii (Warb.) de Laub, should be the synonyms forC revoluta because their “stype” specimens are somewhat likeC. revoluta. The Honghe Nature Cycad Reserve forCycas multipinnata andC. hongheensis was recently established in Yunnan. The Debao Cycad Reserve will be established soon. However, most existing cycad reserves
in China have not been so successful because of shortages of funding and poor management. In ex situ conservation the Qingxiushan
Cycad Garden in Nanning, Guangxi, was established. Cycad nurseries have begun to appear in some villages in South China. 相似文献