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Rehabilitation after soft-tissue autograft reconstructions is controversial because there is indirect evidence that some grafts fail by creeping over time. The vulnerability of soft-tissue grafts to creep over healing time and the effects of the load environment during healing on this vulnerability have never been studied specifically. We hypothesized that immobilization would decrease the magnitude of the vulnerability of ligament grafts to creep. Thirty-nine skeletally mature New Zealand White rabbits underwent a standardized medial collateral ligament autograft procedure to the right hindlimb, and 19 of the rabbits also had the limb rigidly pinned into flexion. Subgroups were killed at 3 or 8 weeks, and all isolated tibia/medial collateral ligament/femur complexes were tested for creep at 4.1 MPa under a standardized protocol. Eight normal medial collateral ligament controls were tested similarly. Results showed that all grafts were quantitatively more susceptible to cyclic and static creep than were normal medial collateral ligament controls (p < 0.05). By 3 weeks of healing, immobilization significantly increased the magnitude of the vulnerability of the grafts to cyclic, static, and total creep (all: p < 0.05). Furthermore, the grafts had more unrecovered creep strain than did the controls following a 20-minute recovery period. Contrary to our hypothesis, immobilization resulted in increased vulnerability of these ligament autografts to creep even with this relatively nonprovocative test of short duration and low stress. We postulate that following immobilization, this increase in the magnitude of susceptibility of the grafts to creep will result in functionally significant elongation of the graft if it is exposed to higher loads and over longer periods of time in vivo. 相似文献
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JH Cho DL Nicolae LH Gold CT Fields MC LaBuda PM Rohal MR Pickles L Qin Y Fu JS Mann BS Kirschner EW Jabs J Weber SB Hanauer TM Bayless SR Brant 《Canadian Metallurgical Quarterly》1998,95(13):7502-7507
The idiopathic inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), are chronic, frequently disabling diseases of the intestines. Segregation analyses, twin concordance, and ethnic differences in familial risks have established that CD and UC are complex, non-Mendelian, related genetic disorders. We performed a genome-wide screen using 377 autosomal markers, on 297 CD, UC, or mixed relative pairs from 174 families, 37% Ashkenazim. We observed evidence for linkage at 3q for all families (multipoint logarithm of the odds score (MLod) = 2.29, P = 5.7 x 10(-4)), with greatest significance for non-Ashkenazim Caucasians (MLod = 3.39, P = 3.92 x 10(-5)), and at chromosome 1p (MLod = 2.65, P = 2.4 x 10(-4)) for all families. In a limited subset of mixed families (containing one member with CD and another with UC), evidence for linkage was observed on chromosome 4q (MLod = 2.76, P = 1.9 x 10(-4)), especially among Ashkenazim. There was confirmatory evidence for a CD locus, overlapping IBD1, in the pericentromeric region of chromosome 16 (MLod = 1.69, P = 2.6 x 10(-3)), particularly among Ashkenazim (MLod = 1.51, P = 7.8 x 10(-3)); however, positive MLod scores were observed over a very broad region of chromosome 16. Furthermore, evidence for epistasis between IBD1 and chromosome 1p was observed. Thirteen additional loci demonstrated nominal (MLod > 1.0, P < 0.016) evidence for linkage. This screen provides strong evidence that there are several major susceptibility loci contributing to the genetic risk for CD and UC. 相似文献
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H Ellegren 《Canadian Metallurgical Quarterly》1993,24(5):367-372
A computer analysis revealed that the mononucleotide repeat (A)n.(T)n is about five times as common as (CA)n.(GT)n repeats in the porcine genome, with frequency estimates of one every 7kb and 30kb, respectively. Seven mononucleotide repeats with n = 12-25 located close to coding sequences were analysed for polymorphism using polymerase chain reaction (PCR) amplification and polyacrylamide gel electrophoresis. All loci were variable with 3-6 alleles and heterozygosities of 0.26-0.69 based on investigation of 10 unrelated pigs (two wild boars and eight domestic sows). Repeat length correlated with degree of polymorphism. A comparison with (CA)n.(GT)n polymorphisms suggested that the number of repeat units rather than the total length of the repeat region is the common denominator that governs polymorphism at both mono- and dinucleotide repeat loci. (A)n.(T)n polymorphisms allowed linkage mapping of relaxin to chromosome 1, apolipoprotein B to chromosome 3, aminopeptidase N to chromosome 7, arachidonate 12-lipoxygenase to chromosome 12, and follistatin to chromosome 16. The rich abundance of potentially informative (A)n.(T)n repeats will increase the chances of finding a PCR-based marker near any DNA sequence of interest. 相似文献
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We explore three explanations of the age trends in susceptibility to leading questions that were reported by Ceci, Ross, and Toglia (1987). The first explanation, that proposed by Ceci et al., is that suggestibility effects are memorially real (i.e., leading questions actually distort target memory) and the magnitudes of such effects vary ontogenetically. The second explanation is that suggestibility effects are memorially real, but they are developmentally invariant. Apparent age changes in suggestibility are said to arise from correlated (and uncontrolled) changes in learning or forgetting rates. The third explanation is that suggestibility effects are not memorially real but, rather, are epiphenomena of certain performance advantages that are intrinsic to control conditions, such as the distractor novelty effect and the retention enhancement effect. Here, apparent age changes in suggestibility are viewed as artifacts of chronological shifts in subjects' ability to benefit from these performance advantages. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Y Katsuyama H Inoko T Imanishi N Mizuki T Gojobori M Ota 《Canadian Metallurgical Quarterly》1998,48(3):126-137
The genetic polymorphism at four variable number of tandem repeats (D1S80, D4S43, COL2A1, D17S5) and one short tandem repeat (ACTBP2) loci was assessed by polymerase chain reaction analysis of genomic DNA obtained from blood samples of eight human populations (Japanese, Northern Han, Hui, Uygur, Kazakh, Saudi Arabian, Greek, Italian). Allele frequencies at all loci were in the Hardy-Weinberg equilibrium for each population. With the exception of ACTBP2, the allelic distribution patterns for these loci revealed a marked genetic divergence among the eight populations. A dendrogram constructed by the neighbor-joining method based on the allele frequencies of the five loci suggested that the five Asian populations (Japanese, Northern Han, Hui, Uygur, and Kazakh) formed one cluster, whereas the two European populations and one West Asian population (Italian, Greek, and Saudi Arabian) formed another. The genetic relationship among these populations may have been greatly influenced by admixture as a result of the migration of individuals along the Silk Road throughout history. 相似文献
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C. S. Carver and E. Harmon-Jones (see record 2009-02580-003) have made an important contribution to the understanding of anger, its linkage to higher order dimensions of emotion, and potential neurobiological substrates. The authors believe, however, that their model and future research conducted to test it would be improved by a more precise explication and parsing of the primary constructs, a clearer articulation of the relation between anger and approach, and the use of methods for assessing brain activation that are more precise than the electroencephalogram. Neuroimaging studies reviewed generally fail to corroborate several features of their model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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5S ribosomal gene spacer sequences from the short-spacer arrays of wheat and rye were isolated by PCR. The 29 new DNA sequences displayed noticeable heterogeneity at scattered positions. Nevertheless, based on shared DNA sequence polymorphisms, sequence alignment clearly classified the sequences into three groups. Group-specific primer sets were designed to allow chromosomal assignment by PCR on nullitetrasomic wheat stocks, as well as on wheat-rye translocation and addition lines. The three groups were assigned to orthologous loci 5S-Rrna-B1, 5S-Rrna-D1, and 5S-Rrna-R1 on homoeologous chromosomes 1B, 1D, and 1R, respectively. Hence, group-specific DNA sequence variation could be related to fixed orthologous DNA sequence variation between 5S rRNA multigene families on the homoeologous group 1 chromosomes. In addition, members of the three groups showed fixed orthologous length polymorphism. Four sequenced 5S-Rrna-B1 units, however, had a duplication in the gene encoding region and are probably representatives of a nontranscribed subfamily of 5S rDNA repeating units. The observed chromosome-specific polymorphisms among sequences belonging to a multigene family with thousands of copies suggests that this type of polymorphism may exist in many genes and gene families in polyploid wheats. The implication of this finding in relation to the construction of molecular tools for wheat-genome analysis and manipulation is discussed. 相似文献
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Morrongiello Barbara A.; Corbett Michael; Bellissimo Alexandra 《Canadian Metallurgical Quarterly》2008,27(4):498
Objective: Although there is considerable speculation that family-based socialization processes influence children's safety and risk behaviors, few studies have addressed this important issue. The present study compared the impact of parent practices and teaching about safety on children's current behaviors and their intended future behaviors when they reach adulthood. Design and Measures: Children 7 to 12 years of age were interviewed and asked to report on their parents' practices and teachings (discussions, expectations for children's behavior) regarding five common safety behaviors. As well, the children reported on their own current practices and how they intended to behave when an adult. When appropriate, they provided explanations about why their parents engage in fewer safety behaviors than they required of their children. Results: Children's current behavior was best predicted by parental teaching, however, how children planned to behave when they were adults was best predicted by parents' practices. Children attributed less frequent safety behaviors by their parents than themselves to general attributes of adults and their parent having special skills that made the safety practices less necessary than was true for children. Conclusion: These results highlight family influences on children's adoption of safety and risk practices and support the notion of intergenerational transmission of risk behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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V. M. Sloutsky and A. V. Fisher (see record 2004-14313-002) reported 5 experiments documenting relations among categorization, induction, recognition, and similarity in children as well as adults and proposed a new model of induction, SINC (similarity, induction, categorization). Those authors concluded that induction depends on perceptual similarity rather than conceptual knowledge. Despite the useful contributions of this work, there are some important limitations. The experimental designs examined a limited range of phenomena that are not the most revealing about the use of nonperceptual information. The main results involved a simple triad task, for which the SINC model's predictions are equivalent to the predictions of previous models of inductive reasoning. It is also unclear whether the SINC model can account for the observed relations between similarity and recognition. Implications for future work on induction and related cognitive activities are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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F Enlund L Samuelsson C Enerb?ck A Inerot J Wahlstr?m M Yhr A Torinsson T Martinsson G Swanbeck 《Canadian Metallurgical Quarterly》1999,49(1):2-8
Angiogenesis is the growth of new blood vessels from existing ones and is critical for tumour development, invasion and metastasis. In bladder cancer the prognostic significance of mean vascular density, a surrogate for angiogenesis, has lead to study of the factors determining the angiogenic phenotype. The motivation for these studies has been the search for non-invasive prognostic or diagnostic markers for the disease and for new therapeutic strategies against bladder cancer recurrence and progression. Whilst a large number of factors are involved in the mediation of tumour angiogenesis, vascular endothelial growth factor (VEGF) is widely considered to be central to the process. This review highlights the information presently available regarding the role of VEGF in bladder cancer through observational studies of its expression in bladder tumours and within the urine. In addition the value of VEGF in determining the prognosis in bladder cancer and the future possibilities for anti-VEGF therapy are discussed. 相似文献
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H Caron M Peter P van Sluis F Speleman J de Kraker G Laureys J Michon L Brugières PA Vo?te A Westerveld 《Canadian Metallurgical Quarterly》1995,4(4):535-539
Previous reports on possible genomic imprinting of the neuroblastoma tumour suppressor gene on chromosome 1p36 have been conflicting. Here we report on the parental origin of 1p36 alleles lost in 47 neuroblastomas and on a detailed Southern blot analysis of the extent of the 1p deletions in 38 cases. The results are remarkably different for tumours with and without N-myc amplification. In the N-myc single copy tumours we show that the lost 1p36 alleles are of preferential maternal origin (16 of 17 cases) and that the commonly deleted region maps to 1p36.2-3. In contrast, all N-myc amplified neuroblastomas have larger 1p deletions, extending from the telomere to at least 1p35-36.1. These deletions are of random parental origin (18 of 30 maternal LOH). This strongly suggests that different suppressor genes on 1p are inactivated in these two types of neuroblastoma. Deletion of a more proximal suppressor gene is associated with N-myc amplification, while a distal, probably imprinted, suppressor can be deleted in N-myc single copy cases. 相似文献
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Using a 1-year prospective design, this study examined the influence of family status variables (family income, parental education, family structure), parenting variables (maternal support and restrictive control), peer support, and neighborhood risk on the school performance of 120 African American junior high school students. In addition to main effects of these variables, neighborhood risk was examined as a moderator of the effects of parenting and peer support. Family status variables were not predictive of adolescent school performance as indexed by self-reported grade point average. Maternal support at Time 1 was prospectively related to adolescent grades at Time 2. Neighborhood risk was related to lower grades, while peer support predicted better grades in the prospective analyses. Neighborhood risk also moderated the effects of maternal restrictive control and peer support on adolescent grades in prospective analyses. These findings highlight the importance of an ecological approach to the problem of academic underachievement within the African American Community. 相似文献
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71 male undergraduates completed the Jenkins Activity Survey—Form T and were typed as showing Type A (coronary prone), Type B (noncoronary prone), or intermediate behavior. Ss were given an opportunity to aggress against a stranger who previously had either provoked or not provoked them. The opportunity to aggress (as well as all other aspects of the study) took place in the presence of a high, moderate, or low (ambient) concentration of negative air ions. Exposure to moderate or high levels of negative ions significantly enhanced aggression by Type A's but not by other Ss. In addition, negative ions produced positive shifts in Ss' reported moods on the Profile of Mood States in the absence of provocation, but negative shifts in moods in the presence of provocation. Findings suggest that moderate or high concentrations of negative ions serve as a source of heightened activation, thus enhancing individuals' dominant reactions or tendencies in a given situation. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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H Mehenni JL Blouin U Radhakrishna SS Bhardwaj K Bhardwaj VB Dixit KF Richards A Bermejo-Fenoll AS Leal RC Raval SE Antonarakis 《Canadian Metallurgical Quarterly》1997,61(6):1327-1334
Peutz-Jeghers syndrome (PJS) is an autosomal dominant disease with variable expression and incomplete penetrance, characterized by mucocutaneous pigmentation and hamartomatous polyposis. Patients with PJS have increased frequency of gastrointestinal and extraintestinal malignancies (ovaries, testes, and breast). In order to map the locus (or loci) associated with PJS, we performed a genomewide linkage analysis, using DNA polymorphisms in six families (two from Spain, two from India, one from the United States, and one from Portugal) comprising a total of 93 individuals, including 39 affected and 48 unaffected individuals and 6 individuals with unknown status. During this study, localization of a PJS gene to 19p13.3 (around marker D19S886) had been reported elsewhere. For our families, marker D19S886 yielded a maximum LOD score of 4.74 at a recombination fraction (theta) of .045; multipoint linkage analysis resulted in a LOD score of 7.51 for the interval between D19S886 and 19 pter. However, markers on 19q13.4 also showed significant evidence for linkage. For example, D19S880 resulted in a maximum LOD score of 3.8 at theta = .13. Most of this positive linkage was contributed by a single family, PJS07. These results confirm the mapping of a common PJS locus on 19p13.3 but also suggest the existence, in a minority of families, of a potential second PJS locus, on 19q13.4. Positional cloning and characterization of the PJS mutations will clarify the genetics of the syndrome and the implication of the gene(s) in the predisposition to neoplasias. 相似文献
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This study investigates the role of autonomy and workload in explaining responses of temporary employees (N=189) compared with permanent employees (N=371) on job satisfaction, organizational commitment, life satisfaction, and performance. Results based on regression analyses suggest that the effects of contract type are not mediated by autonomy or by workload. Rather, this study partially supports hypotheses on the differential reactions of temporaries and permanents to autonomy or workload; autonomy was not predictive for temporaries' job satisfaction and organizational commitment, and workload was not predictive for temporaries' life satisfaction, whereas they were predictive for permanents' responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献