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941.
942.
William Owusu Walter Willett Alberto Ascherio Donna Spiegelman Eric Rimm Diane Feskanich Graham Colditz 《Obesity (Silver Spring, Md.)》1998,6(1):12-19
Available epidemiological information on the associations between body anthropometry and the incidence of fractures in men is limited. We therefore prospectively investigated the association between body anthropometry and the incidence of hip and wrist fractures from low and moderate trauma among 43,053 men who were 40 years to 75 years of age in 1986 when they first enrolled in the Health Professionals Follow-Up Study. After 8 years of follow-up, 201 wrist fracture cases and 56 hip fracture cases were reported. Greater height was associated with significant elevations in both hip and wrist fractures, whereas nonsignificant inverse associations were observed with weight and body mass index. Men in the highest quintile of waist circumference had a relative risk (RR) of 2.57 (95% confidence interval [CI] 0.64 to 10.3) for hip fracture and 2.05 (95% CI 1.06 to 3.96) for wrist fracture when compared with men in the lowest quintile. Waist-to-hip ratio was also positively related to fracture incidence; comparing highest with lowest quintile, the RRs were 3.92 (95% CI 1.07 to 14.3) for hip fracture and 1.50 (95% CI 0.85 to 2.66) for wrist fracture. These anthropometric indicators, in particular waist-to-hip ratio, may be useful for the prediction of hip fracture in adult men. 相似文献
943.
944.
Gilbert G. Walter 《Mathematical biosciences》1984,71(2):181-199
The “spread” of the nonzero eigenvalues of a compartmental matrix is studied by reference to the associated directed graph. It is related to the eigenvalues of the matrices of the individual cycles for certain strongly connected directed graphs. The equilibrium solution to the entire model is also an equilibrium solution to the model consisting of the individual cycles. 相似文献
945.
M. Walter K. Isensee T. Kottke X. Ligneau J.-C. Camelin J.-C. Schwartz H. Stark 《Bioorganic & medicinal chemistry letters》2010,20(19):5883-5886
With a small series of compounds we demonstrated the variability in the core region of the human histamine H3 receptor (hH3R) antagonist structural blueprint by introducing polar azole groups (oxazole, oxadiazole, thiazole and triazole). Additional variations achieved by coupling different residues to the heterocyclic core structure led to further optimisation of in vitro receptor binding of the novel azole derivatives. 相似文献
946.
Low‐input meadows are now recognized for their high biodiversity value and form an integral element of many agri‐environmental schemes in Europe. Meadow mowing techniques, however, have become highly mechanized in recent decades and scientific knowledge on the direct impacts of these techniques on field fauna is based on very few and often poorly replicated studies. Yet these studies, despite their limitations, suggest that such impacts can be considerable. With a view to providing a more comprehensive experimental assessment, we evaluated the direct impacts of four different mowing techniques (hand motor mower with cutter bar, rotary mower cut at 9 cm and rotary mower cut at 6 cm with and without a conditioner) on wax invertebrate models and real caterpillars. The size of the organisms, their microhabitat, the tractor wheel effect and the cutting height were also investigated as factors that could potentially affect mowing‐caused mortality. Rotary mowers were found to be more damaging than motor bar mowers on caterpillars (37% vs. 20%), but only on one type of invertebrate wax‐model. Conditioners more than doubled damage to all wax‐models in the vegetation (in average from 11% to 30%) and increased caterpillar mortality from 38% to 69%. Larger organisms were more vulnerable than smaller organisms and ground organisms were strongly impacted by tractor wheels. While conditioner should not be used in meadows where conservation of the inhabiting fauna is of concern, we also recognize that there is no damage‐free mowing technique. We therefore advocate the importance of leaving uncut areas as a refuge for invertebrates. 相似文献
947.
Cross-compatible relatives of crop species contribute to the uncertainty regarding the potential risk of transgene escape from genetically modified varieties. The most successful crossing partner of oilseed rape (Brassica napus L.) is diploid Brassica rapa L. Variation of ploidy level among B. rapa cultivars has, until recently, been neglected in the context of gene flow and hybridisation with oilseed rape. We estimated the extent of hybridisation between autotetraploid B. rapa varieties (female) and B. napus (pollen donor) under experimental field conditions. Morphology, variation of relative DNA amount, and microsatellite markers were used to distinguish between intraspecific offspring of tetraploid B. rapa and interspecific hybrids with B. napus. Of 517 seed progenies of tetraploid B. rapa, 45 juvenile plants showed species specific morphological traits of oilseed rape. The detection of putative hybrids based on variation in relative DNA amounts was problematic due to the occurrence of aneuploidy. In total, 84 offspring showed relative DNA amounts deviating from tetraploid B. rapa, four of which were hexaploids. Of the 205 offspring analysed at three microsatellite loci, 67 had oilseed rape alleles. Based on molecular evidence a minimum hybridisation rate of 13.0% was estimated. A few mother plants accounted for the majority of hybrids. The mean pollen viability of hybrids between B. napus and tetraploid B. rapa (80.6%) was high in comparison with mean pollen viability of triploid hybrids between B. napus and diploid B. rapa. Therefore, the occurrence of tetraploid B. rapa should be taken into consideration when estimating the likelihood of gene flow from oilseed rape to close relatives at the landscape level. Tetraploid B. rapa is a common component of several seed mixtures and establishes feral populations in northwest Germany. Assuming a similar abundance of diploid and tetraploid B. rapa, gene flow from B. napus to tetraploid may be more likely than gene flow to diploid B. rapa. 相似文献
948.
Sen Utpal; Tyagi Neetu; Kumar Munish; Moshal Karni S.; Rodriguez Walter E.; Tyagi Suresh C. 《American journal of physiology. Cell physiology》2007,293(6):C1779
Although elevated levels of homocysteine (Hcy) known as hyperhomocysteinemia (HHcy) are associated with increased inflammation and vascular remodeling, the mechanism of Hcy-mediated inflammation and vascular remodeling is unclear. The matrix metalloproteinases (MMPs) and adhesion molecules play an important role in vascular remodeling. We hypothesized that HHcy induces inflammation by increasing adhesion molecules and matrix protein expression. Endothelial cells were supplemented with high methionine, and Hcy accumulation was measured by HPLC. Nitric oxide (NO) bioavailability was detected by a NO probe. The protein expression was measured by Western blot analysis. MMP-9 activity was detected by gelatin-gel zymography. We demonstrated that methionine supplement promoted upregulation of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) through increased Hcy accumulation. In addition, increased synthesis of collagen type-1 was also observed. MMP-9 gene expression and protein activity were increased in methionine supplement groups. 3-Deazaadenosine (DZA), an adenosine analogue, prevented high methionine-induced ICAM-1 and VCAM-1 expression and collagen type-1 synthesis. Transfection of endothelial cells with cystathionine-β-synthase (CBS) gene construct, which converts Hcy to cystathionine, reduced Hcy accumulation in high methionine-fed cells. CBS gene transfection reduced the inflammatory response, as evident by attenuated ICAM-1 and VCAM-1 expression. Furthermore, collagen type-1 expression and MMP-9 activity were dramatically attenuated with CBS gene transfection. These results suggested that methionine supplement increased Hcy accumulation, which was associated with inflammatory response and matrix remodeling such as collagen type-1 synthesis and MMP-9 activity. However, in vitro DZA and CBS gene therapy successfully treated the HHcy-induced inflammatory reaction in the methionine metabolism pathway. extracellular matrix; matrix metalloproteinase-9; intercellular cell adhesion molecule-1; vascular cell adhesion molecule-1; collagen type-1; hyperhomocysteinemia 相似文献
949.
Mitotic homologous recombination is utilised to repair DNA breaks using either sister chromatids or homologous chromosomes as templates. Because sister chromatids are identical, exchanges between sister chromatids have no consequences for the maintenance of genomic integrity unless they involve repetitive DNA sequences. Conversely, homologous chromosomes might differ in genetic content, and exchanges between homologues might lead to loss of heterozygosity and subsequent inactivation of functional genes. Genomic instability, caused by unscheduled recombination events between homologous chromosomes, is enhanced in the absence of RecQ DNA helicases, as observed in Bloom's cancer-prone syndrome. Here, we used two-dimensional gel electrophoresis to analyse budding yeast diploid cells that were modified to distinguish replication intermediates originating from each homologous chromosome. Therefore, these cells were suitable for analysing the formation of inter-homologue junctions. We found that Rad51-dependent DNA structures resembling inter-homologue junctions accumulate together with sister chromatid junctions at damaged DNA replication forks in recQ mutants, but not in the absence of Srs2 or Mph1 DNA recombination helicases. Inter-homologue joint molecules in recQ mutants are less abundant than sister chromatid junctions, but they accumulate with similar kinetics after origin firing under conditions of DNA damage. We propose that unscheduled accumulation of inter-homologue junctions during DNA replication might account for allelic recombination defects in recQ mutants. 相似文献
950.