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41.
Lesser bare–backed bats (Dobsonia minor [Pteropodidae]) are solitary and roost in foliage of understory and subcanopy trees in lowland rain forest. These 70–90 gram frugivorous bats forage in primary and secondary forest and in abandoned gardens. At the Kau Wildlife Area in Papua New Guinea, movements (N = 1041) of four males and four females fitted with radio transmitters were monitored for 1 to 18 months. Mean home range within 30–day sampling periods was 5.1 ha (N = 12). There were no significant differences in home ranges by sex or by dry–wet season. Females, however, had significandy larger mean core–use areas than males (1.43 ± 0.61 and 0.65 ±0.16 ha, respectively). There was moderate overlap in home range and core–use areas among some simultaneously tracked animals. The long axes of home ranges varied from 150 to 1150 m and the mean was significantly larger in females. Individuals commuted from day roosts to multiple feeding areas, sometimes resulting in disjunct core–use areas and home ranges. Fruits of native Fiats species and the exotic shrub Piper attuncum were staple food items. Piper aduncum grew as dense clusters within early successional habitats, and individual plants ripened 5–20 fruits per night throughout the year. Ficus spp. grew in primary and secondary forest and fruited asynchronously, but individual trees produced tens to thousands of ripe fruits over 7 to 10 days. Three adult female D. minor were tracked over multiple periods spanning 2.5–18 months. Although each female continued to visit a core–use area containing P. aduncum throughout the study, turnover of other core–use areas reflected the ephemeral locations of fruiting fig trees.  相似文献   
42.
Aging NZB × SJL (NS) female mice provide a unique model of thymopathology characterized by the intrathymic accumulation of large numbers of mature T and B cells. The purpose of the present work was to examine the possibility that this phenomenon results from the invasion of the thymus by cells from the periphery. Lymphoid cells labeled with chromium-51 or indium-111 were injected into syngeneic recipients to study their patterns of in vivo migration. Lymph node (LN) or spleen cells were found to localize significantly (1–2% of injected radioactivity) into the thymus of 12-month-old NS females but not into that of young recipients or of old NS males. However, intrathymic localization of injected LN cells was observed in castrated NS males which exhibit the same thymopathology as NS females. Both radiolabeled T and B cells were found to enter the thymus of aged NS females but the latter cells about three times less efficiently than the former. Moreover, while thymocytes from young NS females were unable to recirculate to LN, those of old NS females showed increased LN-seeking capacity and part (1%) of them did migrate back into the thymus of old but not young NS females. In additional cell transfer experiments, the intrathymic migration of B cells into old NS females was further documented by using the antibody response to sheep erythrocytes as a tracer. Taken together, these observations indicate that the thymus of aging NS female mice is permeable to recirculating lymphocytes, suggesting that at least part of the mature T and B cells detected in this thymus, are migrants from the periphery.  相似文献   
43.
Summary The purpose of this phase I study was to evaluate the toxicity and biological activity of autologous blood-derived macrophages activated ex-vivo with recombinant human interferon (rhuIFN) [monokine-activated killer (MAK) cells] and administered intravenously to 11 lung cancer patients once a week for 6 consecutive weeks. Peripheral blood monocytes were collected by leukapheresis and then purified by counterflow elutriation. The MAK cells were generated by culturing the purified monocytes in Teflon bags for 7 days and adding rhuIFN to the cultured cells for the last 18 h. These MAK cells expressed differentiation-associated surface antigen MAX1, and were cytotoxic in vitro against tumour cell line U937. The MAK cells were infused at dose levels from 1 × 107 to 5 × 108 on an intrapatient dose-escalating schedule. No severe adverse side-effects occurred. Toxicity was mild to moderate [primarly fever (75%) and chills (32%)], non-dose-dependent, and non-cumulative. No consistent change in haemostatic function, or liver or renal function was observed. Dose-limiting toxicity was not reached at 5 × 108 cells (optimal dose reproduced for each patient). The maximum tolerated dose was not determined. The immunomodulatory activity of i.v. infused MAK cells was demonstrated both in vivo by significant increases in granulocyte count and neopterin level in the patients' peripheral blood postinfusion and in vitro by secretory products (IL-1. TNF, neopterin, and thromboplastin-like substance) in the culture supernatants. The in vivo traffic patterns of autologous MAK cells labelled ex-vivo with111In oxine were studied in 7 patients. Gamma imaging showed an immediate but transient lung uptake (<24 h), and a progressive uptake of radioactivity in the liver and spleen was seen from 6 h to 72 h post-infusion. Our results indicate that the preparation of high numbers of autologous, blood-derived MAK cells is a feasible procedure, and their transfusion is safe for patients. This immunotherapeutic approach seems to be encouraging from the point of view of establishing an adjuvant therapeutic modality in cancer patients with minimal residual disease.This work was supported in part by a grant 6911 from the Association pour la Recherche contre le Cancer (ARC), grants from the Ligue Nationale contre le cancer and the Ligues Regionales (Bas-Rhin, Haut-Rhin) contre le cancer, and contract 891013 from the Institut National pour la Santé et la Recherche Médicale (INSERM), France  相似文献   
44.
Muscarinic receptor binding was measured in rat forebrain preparations using the muscarinic agonist, [3H]cis methyldioxolane ([3H]CD). The results of equilibrium binding studies using [3H]CD concentrations between 0.5–64 nM showed that [3H]CD binding did not saturate in this concentration range, although the binding isotherm was concave downward. Nonlinear regression analysis of the binding data revealed the presence of two populations of muscarinic receptors having dissociation constants of 1.83 and 123 nM and binding capacities of 85 and 1320 fmol/mg protein, respectively. Competitive inhibition experiments showed that [3H]CD binding was readily displaced by several muscarinic agonists and antagonists. The stereospecificity of [3H]CD binding was demonstrated in competitive inhibition experiments using the stereoisomers of benzetimide and acetyl-β-methylcholine. Dexetimide was 10,000 times more potent than levetimide and l-acetyl-β-methylcholine was 520 times more potent than d-acetyl-β-methylcholine. A variety of nonmuscarinic cholinergic drugs were not effective at inhibiting [3H]CD binding at a concentration of 10 μM.  相似文献   
45.
The chemical functionalization of cell-surface proteins of human primary fetal bone cells with hydrophilic bioorthogonal intermediates was investigated. Toward this goal, chemical pathways were developed for click reaction-mediated coupling of alkyne derivatives with cellular azido-expressing proteins. The incorporation via a tetraethylene glycol linker of a dipeptide and a reporter biotin allowed the proof of concept for the introduction of cell-specific peptide ligands and allowed us to follow the reaction in living cells. Tuning the conditions of the click reaction resulted in chemical functionalization of living human fetal osteoblasts with excellent cell survival.  相似文献   
46.
The aim of this work was to investigate some aspects of the thyroid epithelial cell kinetics during the iodide-induced involution of a hyperplastic goitre in the rat. Rats were made iodine-deficient for 6 months, and propylthiouracil (PTU) (0.15%) was added to the diet during the last 2 months. Thereafter, rats were refed with iodide and PTU was removed (day 0). Forty-eight hours previously, all the rats were injected with tritiated thymidine ([3H]TdR) (1 microCi/g). Some animals were killed 1 hr or 24 hr after [3H]TdR injection (i.e. on day -2 and -1, day 0 corresponding to the restoration of a normal iodine diet); the other animals were killed after different delay periods and following [3H]TdR injection. Autoradiography of thyroid sections, iodine determination of plasma iodide and protein-bound iodine (PBI), and RIA of plasma thyroid stimulatory hormone (TSH) were performed. Plasma TSH concentration was very high on day 0 of iodide refeeding (3000 +/- 330 ng/ml) and remained at this level until day 8. Plasma PBI was very low on day 0, remained so until day 4 and greatly increased on day 8. Plasma iodide was also very low on day 0, but markedly increased on day 1, then did not vary significantly until day 43 of iodine refeeding. Thyroid weight, elevated on day 0, decreased relatively quickly until day 30, then more slowly until day 73. The [3H]TdR labelling index (LI) of the thyroid epithelial cells (TEC) was high on day 0 (56 +/- 3 labelled cells/10,000 cells), and 24 hr thereafter increased to 104 +/- 3, by division of the labelled cells. On day 1 of iodine refeeding, the LI had abruptly decreased to about half this value and then remained stable for 3 more days. Between day 4 and day 16, a progressive decline in the LI, (by about 3-4 per day), was observed. The LI showed no further modification, up to day 73, the longest period investigated. The decrease in LI occurred without any significant changes in the labelling intensity (grain count) of the remaining labelled cells between day 1 and 16, this indicates that no cell division took place during this period. The data are therefore interpreted as showing a biphasic elimination after iodide refeeding, of cells that were actively proliferating during the goitrous state.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
47.
[Purpose] To determine whether physical activity (PA), primarily the recommended 60 minutes of moderate-to-vigorous PA, is associated with gut bacterial microbiota in 10-year-old children.[Methods] The Block Physical Activity Screener, which provides minutes/day PA variables, was used to determine whether the child met the PA recommendations. 16S rRNA sequencing was performed on stool samples from the children to profile the composition of their gut bacterial microbiota. Differences in alpha diversity metrics (richness, Pielou’s evenness, and Faith’s phylogenetic diversity) by PA were determined using linear regression, whereas beta diversity (unweighted and weighted UniFrac) relationships were assessed using PERMANOVA. Taxon relative abundance differentials were determined using DESeq2.[Results] The analytic sample included 321 children with both PA and 16S rRNA sequencing data (mean age [SD] =10.2 [0.8] years; 54.2% male; 62.9% African American), where 189 (58.9%) met the PA recommendations. After adjusting for covariates, meeting the PA recommendations as well as minutes/day PA variables were not significantly associated with gut richness, evenness, or diversity (p ≥ 0.19). However, meeting the PA recommendations (weighted UniFrac R2 = 0.014, p = 0.001) was significantly associated with distinct gut bacterial composition. These compositional differences were partly characterized by increased abundance of Megamonas and Anaerovorax as well as specific Christensenellaceae_R-7_group taxa in children with higher PA.[Conclusion] Children who met the recommendations of PA had altered gut microbiota compositions. Whether this translates to a reduced risk of obesity or associated metabolic diseases is still unclear.  相似文献   
48.
We tested the long-term effects of sublethal oxidative stresses on replicative senescence. WI-38 human diploid fibroblasts (HDFs) at early cumulative population doublings (CPDs) were exposed to five stresses with 30 microM tert-butylhydroperoxide (t-BHP). After at least 2 d of recovery, the cells developed biomarkers of replicative senescence: loss of replicative potential, increase in senescence-associated beta-galactosidase activity, overexpression of p21(Waf-1/SDI-1/Cip1), and inability to hyperphosphorylate pRb. The level of mRNAs overexpressed in senescent WI-38 or IMR-90 HDFs increased after five stresses with 30 microM t-BHP or a single stress under 450 microM H(2)O(2). These corresponding genes include fibronectin, osteonectin, alpha1(I)-procollagen, apolipoprotein J, SM22, SS9, and GTP-alpha binding protein. The common 4977 bp mitochondrial DNA deletion was detected in WI-38 HDFs at late CPDs and at early CPDs after t-BHP stresses. In conclusion, sublethal oxidative stresses lead HDFs to a state close to replicative senescence.  相似文献   
49.
Coloration of phyllopods varies from place to place and from one life stage to another. It ranges from translucent or whitish through gray, blue, green, orange, and reddish. Here, we present experimental evidence for a food- dependent color pattern inThamnocephalus platyurus Packard. The presence or absence of the synthetic pigment trans — — carotene in a baker's yeast diet was the controlling factor. All the 24 old larvae used in the experiment were whitish in color. From day 6 until the end the experiment (day 11), 100% of the shrimps under a diet with synthetic trans — — carotene (treatment 1) exhibited a characteristic color pattern which consisted of an orange color in the cercopods, and in all theracopods; the rest of the body exhibited no particular color. In comparison, 100% of the shrimps under a diet without synthetic trans — — carotene (treatment 2) were whitish throughout the body. In females from treatment 1, the ovaries and oocytes were green-bluish, while in females from treatment 2 the ovaries and oocytes were whitish. No significant differences in survival and growth were found, except that at day 9, there was a significant difference in growth, the females with the synthetic trans — — carotene group growing faster.  相似文献   
50.
The aim of this study was to investigate the role of an arene oxide pathway in the teratogenicity displayed by DPH, a highly effective antiepileptic agent. This approach was carried out by comparing the teratogene potential of DPH and of p2-H-DPH administrated at days 8, 9 and 12 of gestation. The present findings support the hypothesis that substitution of protium by deuterium at the para position of one of the phenyl rings, which favours an arene oxide pathway, causes an increase in some to the teratogenic effects of DPH.  相似文献   
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