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31.
Halligan EP Lowes D Mistry N Dove R Cooke M Evans M Lunec J 《Redox report : communications in free radical research》2007,12(1):86-90
Oxidation of PUFAs in the diet has the potential to be genotoxic and hence carcinogenic. Such carcinogenic processes originate within stem cells of the colon. These cells appear to be predisposed to the carcinogenic process. In colon cells (CRL-1807) exposed to chemical reactions simulating exogenous and endogenous peroxidation reactions, we have observed that undifferentiated cells could mount an effective recombinational repair/TCR response to an endogenous peroxidative DNA damage insult, but not to an external exogenous peroxidative insult as one would encounter from a dietary source. This may suggest that defects in such specific DNA repair may play a role in tumour development in undifferentiated colonocytes exposed to a diet-derived lipid peroxides. 相似文献
32.
Study of the forest canopy has reached a critical stage in its development from a young frontier area of study to a vibrant and coalescing field of investigation and communication. Many current environmental and social issues at global scales (e.g., environmental change, acid deposition, loss of biodiversity) are related directly to our knowledge of forest canopies. I present six activities that are needed to help the vibrant and growing field of forest canopy studies progress efficiently. Enabling canopy researchers to communicate with each other and with those outside our field is an important element to address these issues. The establishment of a graduate-level training program is also a high priority to generate and maintain a healthy discipline. Formal procedures to identify particular forest sites of critical concern should be initiated, and these should include communication of prioritized sites to conservation groups and policy makers. Instilling a sense of wonder and appreciation for organisms and interactions in non-scientists is another important avenue for forest canopy conservation. 相似文献
33.
34.
Nalini M. Nadkarni 《Hydrobiologia》1995,302(2):178-178
Announcement
The International Canopy Network (ICAN) 相似文献35.
Muscular dystrophies (MDs) such as Duchenne muscular dystrophy (DMD), sarcoglycanopathy (Sgpy) and dysferlinopathy (Dysfy)
are recessive genetic neuromuscular diseases that display muscle degeneration. Although these MDs have comparable endpoints
of muscle pathology, the onset, severity and the course of these diseases are diverse. Different mechanisms downstream of
genetic mutations might underlie the disparity in these pathologies. We surmised that oxidative damage and altered antioxidant
function might contribute to these differences. The oxidant and antioxidant markers in the muscle biopsies from patients with
DMD (n = 15), Sgpy (n = 15) and Dysfy (n = 15) were compared to controls (n = 10). Protein oxidation and lipid peroxidation was evident in all MDs and correlated with the severity of pathology, with
DMD, the most severe dystrophic condition showing maximum damage, followed by Sgpy and Dysfy. Oxidative damage in DMD and
Sgpy was attributed to the depletion of glutathione (GSH) and lowered antioxidant activities while loss of GSH peroxidase
and GSH-S-transferase activities was observed in Dysfy. Lower GSH level in DMD was due to lowered activity of gamma-glutamyl
cysteine ligase, the rate limiting enzyme in GSH synthesis. Similar analysis in cardiotoxin (CTX) mouse model of MD showed
that the dystrophic muscle pathology correlated with GSH depletion and lipid peroxidation. Depletion of GSH prior to CTX exposure
in C2C12 myoblasts exacerbated oxidative damage and myotoxicity. We deduce that the pro and anti-oxidant mechanisms could
be correlated to the severity of MD and might influence the dystrophic pathology to a different extent in various MDs. On
a therapeutic note, this could help in evolving novel therapies that offer myoprotection in MD. 相似文献
36.
Liza Bronner Murrison Ramya Ananthakrishnan Sumanya Sukumar Sheela Augustine Nalini Krishnan Madhukar Pai David W. Dowdy 《PloS one》2016,11(2)
Setting
Private practitioners are frequently the first point of healthcare contact for patients with tuberculosis (TB) in India. Inappropriate TB management practices among private practitioners may contribute to delayed TB diagnosis and generate drug resistance. However, these practices are not well understood. We evaluated diagnostic and treatment practices for active TB and benchmarked practices against International Standards for TB Care (ISTC) among private medical practitioners in Chennai.Design
A cross-sectional survey of 228 practitioners practicing in the private sector from January 2014 to February 2015 in Chennai city who saw at least one TB patient in the previous year. Practitioners were randomly selected from both the general community and a list of practitioners who referred patients to a public-private mix program for TB treatment in Chennai. Practitioners were interviewed using standardized questionnaires.Results
Among 228 private practitioners, a median of 12 (IQR 4–28) patients with TB were seen per year. Of 10 ISTC standards evaluated, the median of standards adhered to was 4.0 (IQR 3.0–6.0). Chest physicians reported greater median ISTC adherence than other MD and MS practitioners (score 7.0 vs. 4.0, P<0.001), or MBBS practitioners (score 7.0 vs. 4.0, P<0.001). Only 52% of all practitioners sent >5% of patients with cough for TB testing, 83% used smear microscopy for diagnosis, 33% monitored treatment response, and 22% notified TB cases to authorities. Of 228 practitioners, 68 reported referring all patients with new pulmonary TB for treatment, while 160 listed 27 different regimens; 78% (125/160) prescribed a regimen classified as consistent with ISTC. Appropriate treatment practices differed significantly between chest physicians and other MD and MS practitioners (54% vs. 87%, P<0.001).Conclusion
TB management practices in India’s urban private sector are heterogeneous and often suboptimal. Private providers must be better engaged to improve diagnostic capacity and decrease TB transmission in the community. 相似文献37.
A putative protein translation inhibitory factor encoded by Cotesia plutellae bracovirus suppresses host hemocyte-spreading behavior 总被引:2,自引:0,他引:2
An endoparasitoid, Cotesia plutellae (Hymenoptera: Braconidae), possesses a mutualistic bracovirus (CpBV), which plays significant roles in the parasitized host, Plutella xylostella (Lepidoptera: Plutellidae). CpBV15beta, a viral gene encoded by CpBV, is expressed at early and late parasitization periods, suggesting that it functions to manipulate the physiology of the parasitized host. This paper reports a physiological function of CpBV15beta as an immunosuppressive agent. The effect of CpBV15beta on cellular immunity was analyzed by assessing hemocyte-spreading behavior. Parasitization by C. plutellae caused altered behavior of hemocytes of P. xylostella, in which the hemocytes were not able to attach and spread on glass slides. CpBV15beta was expressed in Sf9 cells using a baculovirus expression system and purified from the culture media. When hemocytes of nonparasitized P. xylostella were incubated with purified CpBV15beta protein, spreading behavior was impaired in a dose-dependent manner at low micro-molar range. This inhibitory effect of CpBV15beta could also be demonstrated on hemocytes of a non-natural host, Spodoptera exigua. CpBV15beta protein significantly inhibited F-actin growth of hemocytes in response to an insect cytokine. Similarly, cycloheximide, a eukaryotic translation inhibitor, strongly inhibited the spreading behavior and F-actin growth of P. xylostella hemocytes. Under in vitro condition, hemocytes of nonparasitized P. xylostella released proteins into the surrounding medium. Upon incubation of hemocytes with either CpBV15beta or cycloheximide, their ability to release protein molecules was markedly inhibited. This study suggests that CpBV15beta suppresses hemocyte behavior by inhibiting protein translation. 相似文献
38.
To understand the ecological roles of epiphytic bryophytes in the carbon (C) and nitrogen (N) cycles of a tropical montane forest, we used samples in enclosures to estimate rates of growth, net production, and N accumulation by shoots in the canopy, and litterbags, to estimate rates of decomposition and N dynamics of epiphytic bryophyte litter in the canopy and on the forest floor in Monteverde, Costa Rica. Growth of epiphytic bryophytes was estimated at 30.0–49.9 percent/yr, net production at 122–203 g/m2/yr, and N accumulation at 1.8–3.0 g N/m2/yr. Cumulative mass loss from litterbags after one and two years in the canopy was 17 ± 2 and 19 ± 2 percent (mean ± 1 SE) of initial sample mass, respectively, and mass loss from litter and green shoots in litterbags after one year on the forest floor was 29 ± 2 and 45 ± 3 percent, respectively. Approximately 30 percent of the initial N mass was released rapidly from litter in both locations. Nitrogen loss from green shoots on the forest floor was greater; about 47 percent of the initial N mass was lost within the first three months. There was no evidence for net N immobilization by litter or green shoots, but the remaining N in litter was apparently recalcitrant. Annual net accumulation of C and N by epiphytic bryophytes was estimated at 37–64 g C/m2/yr and 0.8–1.3 g N/m2/yr, respectively. Previous research at this site indicated that epiphytic bryophytes retain inorganic N from atmospheric deposition to the canopy. Therefore, they play a major role in transforming N from mobile to highly recalcitrant forms in this ecosystem. 相似文献
39.
The objective of the present study was to investigate the effect of alcohol and nicotine consumption on the pathogenesis of choroidal neovascularization (CNV) in rats after laser-photocoagulation. Confocal microscopic analysis demonstrated an increase in CNV complex size in rats fed with alcohol (2.3-fold), nicotine (1.9-fold), and the combination of alcohol and nicotine (2.7-fold) compared with the control groups. Immunohistochemical analysis revealed that alcohol and nicotine consumption increased MAC deposition and VEGF expression in laser spots. Expression of CD59 by RT-PCR and Western blot was drastically reduced in the animals that were fed with alcohol, nicotine and alcohol and nicotine compared to those fed with water alone and this was associated with exacerbation of CNV. 相似文献
40.
This article recapitulates the scientific advancement towards the greener synthesis of silver nanoparticles. Applications of noble metals have increased throughout human civilization, and the uses for nano-sized particles are even more remarkable. “Green” nanoparticle synthesis has been achieved using environmentally acceptable solvent systems and eco-friendly reducing and capping agents. Numerous microorganisms and plant extracts have been applied to synthesize inorganic nanostructures either intracellularly or extracellularly. The use of nanoparticles derived from noble metals has spread to many areas including jewelery, medical fields, electronics, water treatment and sport utilities, thus improving the longevity and comfort in human life. The application of nanoparticles as delivery vehicles for bactericidal agents represents a new paradigm in the design of antibacterial therapeutics. Orientation, size and physical properties of nanoparticles influences the performance and reproducibility of a potential device, thus making the synthesis and assembly of shape- and size-controlled nanocrystals an essential component for any practical application. This need has motivated researchers to explore different synthesis protocols. 相似文献