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11.
Captive nonhuman animals use enclosure space differentially. Enclosure features strongly influence this. This study recorded both the enclosure space used by 47 captive lion-tailed macaques housed in 13 zoos across India and the behavior of the macaques. The exhibition of abnormal behaviors, food-related behaviors, and social interactions correlated significantly with the use of the edge zone (the part of the enclosure closest to the visitor area). Animals housed in barren enclosures used the edge zone to a significantly greater percentage than did those housed in complex exhibits. Percentages of autogrooming, social interactions, and food-related behaviors significantly correlated with the use of the enrich zone. Space use studies assist in recognizing areas within the enclosure, which captive animals actively use. Conversely, the studies can identify areas infrequently used and show how to make maximum use of these enclosure areas. Further studies targeting both the increase in percentages of natural behaviors exhibited and use of the enrich zone used the current study on captive lion-tailed macaques for their design.  相似文献   
12.

Background

While a number of the consequences of mast cell degranulation within tissues have been documented including tissue-specific changes such as bronchospasm and the subsequent cellular infiltrate, there is little known about the immediate effects of mast cell degranulation on the associated vasculature, critical to understanding the evolution of mast cell dependent inflammation.

Objective

To characterize the microcirculatory events that follow mast cell degranulation.

Methodology/Principal Findings

Perturbations in dermal blood flow, temperature and skin color were analyzed using laser-speckle contrast imaging, infrared and polarized-light colorimetry following cold-hand immersion (CHI) challenge in patients with cold-induced urticaria compared to the response in healthy controls. Evidence for mast cell degranulation was established by documentation of serum histamine levels and the localized release of tryptase in post-challenge urticarial biopsies. Laser-speckle contrast imaging quantified the attenuated response to cold challenge in patients on cetirizine. We found that the histamine-associated vascular response accompanying mast cell degranulation is rapid and extensive. At the tissue level, it is characterized by a uniform pattern of increased blood flow, thermal warming, vasodilation, and recruitment of collateral circulation. These vascular responses are modified by the administration of an antihistamine.

Conclusions/Significance

Monitoring the hemodynamic responses within tissues that are associated with mast cell degranulation provides additional insight into the evolution of the acute inflammatory response and offers a unique approach to assess the effectiveness of treatment intervention.  相似文献   
13.
XRCC1 is a critical scaffold protein that orchestrates efficient single-strand break repair (SSBR). Recent data has found an association of XRCC1 with proteins causally linked to human spinocerebellar ataxias—aprataxin and tyrosyl-DNA phosphodiesterase 1—implicating SSBR in protection against neuronal cell loss and neurodegenerative disease. We demonstrate herein that shRNA lentiviral-mediated XRCC1 knockdown in human SH-SY5Y neuroblastoma cells results in a largely selective increase in sensitivity of the nondividing (i.e. terminally differentiated) cell population to the redox-cycling agents, menadione and paraquat; this reduced survival was accompanied by an accumulation of DNA strand breaks. Using hypoxanthine–xanthine oxidase as the oxidizing method, XRCC1 deficiency affected both dividing and nondividing SH-SY5Y cells, with a greater effect on survival seen in the former case, suggesting that the spectrum of oxidative DNA damage created dictates the specific contribution of XRCC1 to cellular resistance. Primary XRCC1 heterozygous mouse cerebellar granule cells exhibit increased strand break accumulation and reduced survival due to increased apoptosis following menadione treatment. Moreover, knockdown of XRCC1 in primary human fetal brain neurons leads to enhanced sensitivity to menadione, as indicated by increased levels of DNA strand breaks relative to control cells. The cumulative results implicate XRCC1, and more broadly SSBR, in the protection of nondividing neuronal cells from the genotoxic consequences of oxidative stress.  相似文献   
14.
15.
The ends of chromosomes, called telomeres, are composed of a DNA repeat sequence and associated proteins, which prevent DNA degradation and chromosome fusion. We have previously used plasmid sequences integrated adjacent to a telomere to demonstrate that mammalian telomeres suppress gene expression, called telomere position effect (TPE). We have also shown that subtelomeric regions are highly sensitive to double-strand breaks, leading to chromosome instability, and that this instability can be prevented by the addition of a new telomere to the break, a process called chromosome healing. We have now targeted the same plasmid sequences to a site 100 kb from a telomere in a human carcinoma cell line to address the effect of telomere proximity on telomere position effect, chromosome healing, and sensitivity to double-strand breaks. The results demonstrate a substantial decrease in TPE 100 kb from the telomere, demonstrating that TPE is very limited in range. Chromosome healing was also diminished 100 kb from the telomere, consistent with our model that chromosome healing serves as a repair process for restoring lost telomeres. Conversely, the region 100 kb from the telomere was highly sensitive to double-strand breaks, demonstrating that the sensitive region is a relatively large target for ionizing radiation-induced chromosome instability.Telomeres are composed of a six-base pair repeat sequence and associated proteins that together form a cap to protect the ends of chromosomes and prevent chromosome fusion (6). Telomeres are actively maintained by the enzyme telomerase in human germ line cells but shorten with age in most somatic cells due to the low level of expression of telomerase (12). When a telomere shortens to the point that it is recognized as a double-strand break (DSB), it serves as a signal for replicative cell senescence (13). Human cells that lose the ability to senesce continue to show telomere shortening and eventually enter crisis, which involves increased chromosome fusion, aneuploidy, and cell death (11, 15). An important step that is required for continued division of cancer cells is therefore that they possess the ability to maintain telomeres, not only to avoid senescence but also to avoid chromosome fusion brought on by crisis (11, 25).In addition to their role in protecting the ends of chromosomes, telomeres can also inhibit the expression of nearby genes, called telomere position effect (TPE). TPE has been proposed to have a role in the cellular response to changes in telomere length (26); however, the function of TPE remains unknown. TPE has been extensively studied in Saccharomyces cerevisiae using transgenes integrated near telomeres on truncated chromosomes (1, 2, 22, 47). These studies demonstrated that TPE involves changes in chromatin conformation and is dependent upon both the distance from the telomere and telomere length (55). Subsequent studies of endogenous yeast genes, however, revealed that the influence of TPE on gene expression varies depending on the presence of insulator sequences (18, 45). TPE also occurs in mammalian cells and has been implicated in the loss of expression of genes relocated near telomeres in a variety of human syndromes (9, 16, 28, 58, 59). As in yeast, transgenes located near telomeres have been used to study TPE in the C33-A (32) and HeLa (4) human cervical carcinoma cell lines. We have also studied TPE using transgenes located adjacent to telomeres in mouse embryonic stem (ES) cells, mouse embryo fibroblasts, and transgenic mice (43). However, none of the studies of TPE in mammalian cells has addressed the distance over which TPE extends from the telomere, and so the number of genes whose expression is likely to be affected is not known.The presence of a telomere can also influence the sensitivity of subtelomeric regions to DSBs. We previously demonstrated the sensitivity of subtelomeric regions to DSBs using selectable transgenes and a recognition site for the I-SceI endonuclease that are integrated immediately adjacent to a telomere. Unlike I-SceI-induced DSBs at most locations, which primarily result in small deletions (27, 34, 46, 50), I-SceI-induced DSBs near telomeres commonly result in large deletions, gross chromosome rearrangements (GCRs), and chromosome instability in both mouse ES cells (37) and human tumor cells (65). Therefore, depending on the size of the sensitive region, the combined targets of the subtelomeric regions on all telomeres could contribute significantly to the genomic instability caused by ionizing radiation or other agents that produce DSBs (35). This sensitivity to DSBs may result from a deficiency in DSB repair since regions near telomeres in yeast are deficient in nonhomologous end joining, resulting in an increase in GCRs (48). One possible reason for a deficiency in DSB repair near telomeres is the role of the telomere in preventing chromosome fusion. Telomeric repeat sequences in yeast have been shown to suppress the activation of cell cycle checkpoints in response to DSBs (39). Similarly, the human TRF2 protein, which is required to prevent chromosome fusion, has been demonstrated to inhibit ATM (31), whose activation is instrumental in the repair of DSBs in heterochromatin (20).One mechanism for avoiding the consequences of DSBs near telomeres is through the addition of a new telomere to the site of a DSB, termed chromosome healing (44). Studies in yeast have shown that chromosome healing occurs through the de novo addition of telomeric repeat sequences by telomerase (14, 33, 38). Chromosome healing in S. cerevisiae is inhibited by the 5′-3′ helicase, Pif1 (52), with Pif1-deficient cells showing up to a 1,000-fold increase in chromosome healing (33, 38). The ability of Pif1 to inhibit chromosome healing has been proposed to serve as a mechanism to prevent chromosome healing from interfering with DSB repair (63). Mammalian cells that express telomerase are also capable of performing chromosome healing. We have shown that chromosome healing can also occur following spontaneous telomere loss (17, 49) or DSBs near telomeres in a human cancer cell line (65) or mouse ES cells (19, 54). We have also shown that chromosome healing can prevent the chromosome instability resulting from DSBs near telomeres (19). Because the de novo addition of telomeric repeat sequences has not been observed in mammalian cells at I-SceI-induced DSBs at interstitial sites (27, 34, 46, 50), we have proposed that chromosome healing is inhibited at most locations but serves as an important mechanism for dealing with DSBs near telomeres that would otherwise result in chromosome instability. However, an alternative possibility that has not been ruled out is that chromosome healing also occurs at interstitial sites but that the large terminal deletions that it causes at these sites results in cell death.In the present study, we address several key questions regarding the importance of telomere proximity on TPE, chromosome healing, and sensitivity to DSBs by investigating how telomere proximity affects these processes. The first of these questions involves establishing the distance over which TPE extends from the telomere to gain insights into the numbers of genes that would be affected by changes in TPE. Second, we will investigate whether chromosome healing can occur at a site that is distant from a telomere but in which terminal deletions are known not to be lethal. This will determine for the first time whether chromosome healing is limited to regions near telomeres. Finally, we will investigate the size of the region near a telomere that is sensitive to DSBs, which will address the potential importance of the subtelomeric region as a target for ionizing radiation-induced genomic instability (35). The distance over which a telomere can exert its effects was investigated by comparing TPE, chromosome healing, and the sensitivity to DSBs at a site 100 kb from a telomere with a site immediately adjacent to the same telomere. As a control for the efficiency of generating DSBs at these sites, we have also analyzed the frequency of small deletions, the most common type of I-SceI-induced DNA rearrangement at interstitial sites in mammalian cells (27, 60). Small deletions serve as an excellent internal control for comparing the frequency of other types of rearrangements since we have previously observed a similar frequency of small deletions at telomeric and interstitial sites (65). The results provide important information on the distance over which a telomere can influence TPE, chromosome healing, and the sensitivity to DSBs.  相似文献   
16.
The photoprotective potential of the dietary antioxidants vitamin C, vitamin E, lycopene, β-carotene, and the rosemary polyphenol, carnosic acid, was tested in human dermal fibroblasts exposed to ultraviolet-A (UVA) light. The carotenoids were prepared in special nanoparticle formulations together with vitamin C and/or vitamin E. Nanoparticle formulations, in contrast to dimethylsulphoxide, stablized lycopene in the cell culture medium and allowed efficient cellular uptake. The presence of vitamin E in the formulation further increased the stability and cellular uptake of lycopene. UVA irradiation of the human skin fibroblasts led to a 10–15-fold rise in metalloproteinase 1 (MMP-1) mRNA. This rise was suppressed in the presence of low μM concentrations of vitamin E, vitamin C, or carnosic acid but not with β-carotene or lycopene. Indeed, in the presence of 0.5–1.0 μM β-carotene or lycopene, the UVA-induced MMP-1 mRNA was further increased by 1.5–2-fold. This increase was totally suppressed when vitamin E was included in the nanoparticle formulation. Heme-oxygenase 1 (HO-1) mRNA expression was strongly induced by UVA irradiation but none of the antioxidants inhibited this effect at the concentrations used in this study. Indeed, β-carotene or lycopene (0.5–1.0 μM) led to a further 1.5-fold rise in the UVA-induced HO-1 mRNA levels. In conclusion, vitamin C, vitamin E, and carnosic acid showed photoprotective potential. Lycopene and β-carotene did not protect on their own but in the presence of vitamin E, their stability in culture was improved and the rise in MMP-1 mRNA expression was suppressed, suggesting a requirement for antioxidant protection of the carotenoids against formation of oxidative derivatives that can influence the cellular and molecular responses.  相似文献   
17.
To eliminate abnormal behaviors in leopards (Panthera pardus), such as stereotypic pacing, by utilizing environmental enrichment techniques, a proper understanding of their behavior in captive environments is required. Hence there is a need for animal welfare studies in Indian zoos. The activity budgets of 16 leopards were recorded across four southern Indian zoos: Thiruvananthapuram Zoo, Arignar Anna Zoological Park, Shri Chamarajendra Zoological Gardens, and the Guindy Children's Park. Of the 16 study animals, 14 were studied on‐exhibit on zoo holidays as well as on days with visitors present, and all 16 individuals were studied off‐exhibit on other days with visitors present. The 11 behaviors recorded were categorized into active, resting, and stereotypic behaviors. Leopards exhibited higher levels of activity in the on‐exhibit enclosures on days with no visitors. Feeding time influenced the behavioral repertoire of all 14 leopards studied on‐exhibit. Lower proportions of resting were exhibited during the hours before feeding. The proportion of active behaviors differed significantly across zoos. Stereotypic pacing levels were not influenced by the presence of visitors or by feeding time, but was significantly influenced by enclosure features. Higher levels of stereotypic pacing were exhibited in off‐exhibit than on‐exhibit enclosures. Our study shows that the behavior of captive leopards is influenced by enclosure type, feeding regime, and the presence of visitors. Zoo Biol 21:585–595, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
18.
Dysbindin assembles into the biogenesis of lysosome-related organelles complex 1 (BLOC-1), which interacts with the adaptor protein complex 3 (AP-3), mediating a common endosome-trafficking route. Deficiencies in AP-3 and BLOC-1 affect synaptic vesicle composition. However, whether AP-3-BLOC-1-dependent sorting events that control synapse membrane protein content take place in cell bodies upstream of nerve terminals remains unknown. We tested this hypothesis by analyzing the targeting of phosphatidylinositol-4-kinase type II α (PI4KIIα), a membrane protein present in presynaptic and postsynaptic compartments. PI4KIIα copurified with BLOC-1 and AP-3 in neuronal cells. These interactions translated into a decreased PI4KIIα content in the dentate gyrus of dysbindin-null BLOC-1 deficiency and AP-3-null mice. Reduction of PI4KIIα in the dentate reflects a failure to traffic from the cell body. PI4KIIα was targeted to processes in wild-type primary cultured cortical neurons and PC12 cells but failed to reach neurites in cells lacking either AP-3 or BLOC-1. Similarly, disruption of an AP-3-sorting motif in PI4KIIα impaired its sorting into processes of PC12 and primary cultured cortical neuronal cells. Our findings indicate a novel vesicle transport mechanism requiring BLOC-1 and AP-3 complexes for cargo sorting from neuronal cell bodies to neurites and nerve terminals.  相似文献   
19.

Background

Low birth weight (LBW) is a major public health problem in many developing countries, especially so in India. Although we do not know all the causes of LBW, maternal and environmental factors appear to be significant risk factors in its occurrence.

Objectives

To know the factors affecting the birth weight of a newborn and to estimate the prevalence of LBW.

Methods

The present study was carried out amongst 1138 pregnant women and their newborns residing in area covered by Kinaye Primary Health Centre in rural Karnataka, India. The study was conducted from 1st June 2008 to 31st December 2009.

Results

The mean birth weight of newborns was 2.6 kg with a range of 1.2 to 3.8 kg. The prevalence of LBW was 22.9%. Among the studied risk factors, 25 of them were significantly associated with the birth weight of a newborn on univariate logistic regression analysis. Maternal education [Odds Ratio (OR) 3.2], exposure to passive smoking [OR 2.3], age at first pregnancy ≥25 years [OR 3.6], birth interval <2 years [OR 2.4], previous history of LBW baby [OR 3.3], weight gain ≤4 kg during pregnancy [OR 7.0], maternal weight at last week of gestation ≤45 kg [OR 2.3], pregnancy induced hypertension [OR 3.3], high risk pregnancy [OR 3.6] and late antenatal registration [OR 3.6] emerged as significant risk factors on multivariate analysis.

Conclusion

The problem of LBW is multidimensional, and hence, we need an integrated approach incorporating medical, social, economical and educational measures to address this issue.  相似文献   
20.
Mast cells, activated by Ag via FcεRI, release an array of proinflammatory mediators that contribute to allergic disorders, such as asthma and anaphylaxis. The KIT ligand, stem cell factor (SCF), is critical for mast cell expansion, differentiation, and survival, and under acute conditions, it enhances mast cell activation. However, extended SCF exposure in vivo conversely protects against fatal Ag-mediated anaphylaxis. In investigating this dichotomy, we identified a novel mode of regulation of the mast cell activation phenotype through SCF-mediated programming. We found that mouse bone marrow-derived mast cells chronically exposed to SCF displayed a marked attenuation of FcεRI-mediated degranulation and cytokine production. The hyporesponsive phenotype was not a consequence of altered signals regulating calcium flux or protein kinase C, but of ineffective cytoskeletal reorganization with evidence implicating a downregulation of expression of the Src kinase Hck. Collectively, these findings demonstrate a major role for SCF in the homeostatic control of mast cell activation with potential relevance to mast cell-driven disease and the development of novel approaches for the treatment of allergic disorders.  相似文献   
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