917 resultados para Repeated Fragments


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Neurotoxic effects of the environmentally abundant mycotoxin Ochratoxin A (OTA) were studied in histotypic 3D rat brain cell cultures, comprising all brain cell types. Cultures were exposed to nanomolar OTA concentrations and samples were collected 48h after a single exposure, or after 10 days of repeated administration. OTA-induced changes in gene- and protein expression, as well as alterations in cell morphology were assessed. Forty-eight-hour OTA exposure resulted in a disruption of the neuronal cytoskeleton and reduced expression of several oligodendrocyte-specific markers indicative of demyelination. Astrocyte disturbances were revealed by a decrease in two astrocytic proteins involved in regulation of inflammatory responses, metallothioneins I and II. Repeated OTA administration induced a neuroinflammatory response, as visualized by an increase of isolectin B4 labelled cells, increased expression of pro-inflammatory cytokines, and detection of macrophagic ED1/CD68 positive cells, as well as an upregulation of neurodegenerative M1 microglial phenotype markers. Partial recovery from OTA-induced deleterious effects on oligodendrocytes and astrocytes was achieved by co-treatment with sonic hedgehog (SHH). In addition, metallothionein I and II co-treatment partially restored OTA-induced effects on oligodendrocytes after 48h, and modulated microglial reactivity after 10 days. These results suggest that OTA-exposure affects Shh-signalling, which in turn may influence both oligodendrocytes and astrocytes. Furthermore, the primarily astrocytic proteins MTI/MTII may affect microglial activation. Thus the neuroinflammatory response appears to be downstream of OTA-induced effects on demyelination, axonal instabilities and astrocytes disturbances. In conclusion, repeated OTA-exposure induced a secondary neuroinflammatory response characterized by neurodegenerative M1 microglial activation and pro-inflammatory response that could exacerbate the neurodegenerative process.

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Fifty-seven patients with suspected CEA-producing tumors were studied prospectively by radioimmunoscintigraphy (RIS) using a 123I-labeled anti-CEA monoclonal antibody (MAb) (essentially the F(ab')2 or Fab fragments) and emission computed tomography (ECT). Results of RIS were compared to those of a comprehensive diagnostic study. Final diagnosis was based on surgery, biopsy and autopsy (n = 39) or follow-up findings (n = 18). Three groups of patients were defined: Group A with suspected primary tumors (n = 11), Group B with probable (n = 19) and Group C with questionable (n = 27) tumor relapse. Eighty-eight per cent, 93% and 71% of the anatomic regions studied were correctly identified as being involved, and 97%, 97%, and 87% as being free from tumor in Groups A, B, and C, respectively. In the 27 patients from Group C with no definite diagnosis of relapse, and in whom diagnosis was most difficult, 38 tumor sites were involved. Of these, 21 were detected by both prospective RIS and repeated comprehensive study, six by RIS only and seven by conventional methods only. Four sites remained undetected by both approaches. Ten of the 21 lesions were detected by RIS more than 1 mo earlier than by any other method. Among the seven tumor sites detected by other diagnostic modalities only, three were identified at the time of RIS and four became positive more than 6 mo later. Overall diagnosis was entirely correct in 30, partially correct in 16 and incorrect in six patients studied. RIS with ECT and 123I-labeled anti-CEA MAb allows early detection of recurrence or metastasis of colorectal cancer. It thus contributes to reduced delay between diagnosis and treatment.

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Introduction: Prior repeated-sprints (6) has become an interesting method to resolve the debate surrounding the principal factors that limits the oxygen uptake (V'O2) kinetics at the onset of exercise [i.e., muscle O2 delivery (5) or metabolic inertia (3)]. The aim of this study was to compare the effects of two repeated-sprints sets of 6x6s separated by different recovery duration between the sprints on V'O2 and muscular de-oxygenation [HHb] kinetics during a subsequent heavy-intensity exercise. Methods: 10 male subjects performed a 6-min constant-load cycling test (T50) at intensity corresponding to half of the difference between V'O2max and the ventilatory threshold. Then, they performed two repeated-sprints sets of 6x6s all-out separated by different recovery duration between the sprints (S1:30s and S2:3min) followed, after 7-min-recovery, by the T50 (S1T50 and S2T50, respectively). V'O2, [HHb] of the vastus lateralis (VL) and surface electromyography activity [i.e., root-mean-square (RMS) and the median frequency of the power density spectrum (MDF)] from VL and vastus medialis (VM) were recorded throughout T50. Models using a bi-exponential function for the overall T50 and a mono-exponential for the first 90s of T50 were used to define V'O2 and [HHb] kinetics respectively. Results: V'O2 mean value was higher in S1 (2.9±0.3l.min-1) than in S2 (1.2±0.3l.min-1); (p<0.001). The peripheral blood flow was increased after sprints as attested by a higher basal heart rate (HRbaseline) (S1T50: +22%; S2T50: +17%; p≤0.008). Time delay [HHb] was shorter for S1T50 and S2T50 than for T50 (-22% for both; p≤0.007) whereas the mean response time of V'O2 was accelerated only after S1 (S1T50: 32.3±2.5s; S2T50: 34.4±2.6s; T50: 35.7±5.4s; p=0.031). There were no significant differences in RMS between the three conditions (p>0.05). MDF of VM was higher during the first 3-min in S1T50 than in T50 (+6%; p≤0.05). Conclusion: The study show that V'O2 kinetics was speeded by prior repeated-sprints with a short (30s) but not a long (3min) inter-sprints-recovery even though the [HHb] kinetics was accelerated and the peripheral blood flow was enhanced after both sprints. S1, inducing a greater PCr depletion (1) and change in the pattern of the fibres recruitment (increase in MDF) compared with S2, may decrease metabolic inertia (2), stimulate the oxidative phosphorylation activation (4) and accelerate V'O2 kinetics at the beginning of the subsequent high-intensity exercise.

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This publication contains fragments of the debates of the Iowa Constitutional Conventions of 1844 and 1846 as preserved in several Iowa newspapers; The Iowa Standard, The Capital Reporter and The Bloomington Herald. These fragments include parts of the debates, press comments and other related materials.

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In this paper we describe the results of a simulation study performed to elucidate the robustness of the Lindstrom and Bates (1990) approximation method under non-normality of the residuals, under different situations. Concerning the fixed effects, the observed coverage probabilities and the true bias and mean square error values, show that some aspects of this inferential approach are not completely reliable. When the true distribution of the residuals is asymmetrical, the true coverage is markedly lower than the nominal one. The best results are obtained for the skew normal distribution, and not for the normal distribution. On the other hand, the results are partially reversed concerning the random effects. Soybean genotypes data are used to illustrate the methods and to motivate the simulation scenarios

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In this paper we analyse, using Monte Carlo simulation, the possible consequences of incorrect assumptions on the true structure of the random effects covariance matrix and the true correlation pattern of residuals, over the performance of an estimation method for nonlinear mixed models. The procedure under study is the well known linearization method due to Lindstrom and Bates (1990), implemented in the nlme library of S-Plus and R. Its performance is studied in terms of bias, mean square error (MSE), and true coverage of the associated asymptotic confidence intervals. Ignoring other criteria like the convenience of avoiding over parameterised models, it seems worst to erroneously assume some structure than do not assume any structure when this would be adequate.

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"De l'autorité et de l'intelligence des chefs" (3 feuilles dactylographiées) ; "Mécanisme des grandes notions de la vie" (8 feuilles dactylographiées) ; "Méthodes d'enseignement et d'éducation" (4 feuilles dactylographiées avec corrections manuscrites) ; "Souvenirs du temps de l'exode" (2 feuilles dactylographiées) ; notes sur l'étude d'un sentiment (18 feuilles dactylographiées en double exemplaire) ; notes biographiques sur Louis Marin (16 feuilles dactylographiées) ; "L'elginisme et la conservation des monuments historiques" (28 feuilles dactylographiées)

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This clinical study was based on experimental results obtained in nude mice grafted with human colon carcinoma, showing that injected 131I-labeled F(ab')2 and Fab fragments from high affinity anti-carcinoembryonic antigen (CEA) monoclonal antibodies (MAb) gave markedly higher ratios of tumor to normal tissue localization than intact MAb. 31 patients with known colorectal carcinoma, including 10 primary tumors, 13 local tumor recurrences, and 21 metastatic involvements, were injected with 123I-labeled F(ab')2 (n = 14) or Fab (n = 17) fragments from MAb anti-CEA. The patients were examined by emission-computerized tomography (ECT) at 6, 24, and sometimes 48 h after injection using a rotating dual head scintillation camera. All 23 primary tumors and local recurrences except one were clearly visualized on at least two sections of different tomographic planes. Interestingly, nine of these patients had almost normal circulating CEA levels, and three of the visualized tumors weighed only 3-5 g. Among 19 known metastatic tumor involvements, 14 were correctly localized by ECT. Two additional liver and several bone metastases were discovered by immunoscintigraphy. Altogether, 86% of the tumor sites were detected, 82% with F(ab')2 and 89% with Fab fragments. The contrast of the tumor images obtained with Fab fragments suggests that this improved method of immunoscintigraphy has the potential to detect early tumor recurrences and thus to increase the survival of patients. The results of this retrospective study, however, should be confirmed in a prospective study before this method can be recommended for the routine diagnosis of cancer.

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This study aimed to determine changes in spring-mass model (SMM) characteristics, plantar pressures, and muscle activity induced by the repetition of sprints in soccer-specific conditions; i.e., on natural grass with soccer shoes. Thirteen soccer players performed 6 × 20 m sprints interspersed with 20 s of passive recovery. Plantar pressure distribution was recorded via an insole pressure recorder device divided into nine areas for analysis. Stride temporal parameters allowed to estimate SMM characteristics. Surface electromyographic activity was monitored for vastus lateralis, rectus femoris, and biceps femoris muscles. Sprint time, contact time, and total stride duration lengthened from the first to the last repetition (+6.7, +12.9, and +9.3%; all P < 0.05), while flight time, swing time, and stride length remained constant. Stride frequency decrease across repetitions approached significance (-6.8%; P = 0.07). No main effect of the sprint number or any significant interaction between sprint number and foot region was found for maximal force, mean force, peak pressure and mean pressure (all P > 0.05). Center of mass vertical displacement increased (P < 0.01) with time, together with unchanged (both P > 0.05) peak vertical force and leg compression. Vertical stiffness decreased (-15.9%; P < 0.05) across trials, whereas leg stiffness changes were not significant (-5.9%; P > 0.05). Changes in root mean square activity of the three tested muscles over sprint repetitions were not significant. Although repeated sprinting on natural grass with players wearing soccer boots impairs their leg-spring behavior (vertical stiffness), there is no substantial concomitant alterations in muscle activation levels or plantar pressure patterns.

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The aim of this study was to determine potential relationships between anthropometric parameters and athletic performance with special consideration to repeated-sprint ability (RSA). Sixteen players of the senior male Qatar national soccer team performed a series of anthropometric and physical tests including countermovement jumps without (CMJ) and with free arms (CMJwA), straight-line 20 m sprint, RSA (6 × 35 m with 10 s recovery) and incremental field test. Significant (P < 0.05) relationships occurred between muscle-to-bone ratio and both CMJs height (r ranging from 0.56 to 0.69) as well as with all RSA-related variables (r < -0.53 for sprinting times and r = 0.54 for maximal sprinting speed) with the exception of the sprint decrement score (Sdec). The sum of six skinfolds and adipose mass index were largely correlated with Sdec (r = 0.68, P < 0.01 and r = 0.55, P < 0.05, respectively) but not with total time (TT, r = 0.44 and 0.33, P > 0.05, respectively) or any standard athletic tests. Multiple regression analyses indicated that muscular cross-sectional area for mid-thigh, adipose index, straight-line 20 m time, maximal sprinting speed and CMJwA are the strongest predictors of Sdec (r(2) = 0.89) and TT (r(2) = 0.95) during our RSA test. In the Qatar national soccer team, players' power-related qualities and RSA are associated with a high muscular profile and a low adiposity. This supports the relevance of explosive power for the soccer players and the larger importance of neuromuscular qualities determining the RSA.

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A repeated DNA element in Xenopus laevis is described that is present in about 7500 copies dispersed throughout the genome. It was first identified in the 5' flanking region of one vitellogenin gene and was therefore named the Vi element. Seven copies are present within the vitellogenin gene region, three of them within introns of the genes A1, A2 and B2, and the other four copies in the gene flanking regions. Four of these copies have been sequenced. The Vi element is bounded by a well-conserved 13 base-pair inverted repeat; in addition, it is flanked by a three base-pair direct repeat that appears to be site-specific. The length of these four copies varies from 112 to 469 base-pairs; however, sequence homology between the different copies is very high. Their structural characteristics suggest that length heterogeneity may have arisen by either unequal recombinations, deletions or tandem duplications. Altogether, the characteristics and properties of the Vi element indicate that it might represent a mobile genetic element. One of the four copies sequenced is inserted close (position -535) to the transcription initiation site of the vitellogenin gene B2 in a region otherwise showing considerable homology with the closely related gene B1. Nevertheless, the presence of the Vi element does not seem to influence significantly the estrogen-controlled expression of gene B2. In addition, three alleles of this gene created by length polymorphism in intron 3 and in the Vi element inserted near the transcription initiation site are described.