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61.
BACKGROUND: Little is known about the cause of inflammatory breast carcinoma (IBC), the most aggressive form of breast cancer. To the authors' knowledge, no studies have investigated whether IBC risk factors are different from those for breast carcinoma overall, and there has been only one report of IBC incidence and survival patterns. METHODS: The authors used data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute for the period 1975-1992 to calculate age-adjusted incidence and survival rates for 913 white and 121 African American women with IBC involving dermal invasion of lymphatic ducts and 166,375 white and 13,674 African American women with other types of breast carcinoma (non-IBC). RESULTS: Between 1975-1977 and 1990-1992, IBC incidence doubled, increasing among whites from 0.3 to 0.7 cases per 100,000 person-years and among African Americans from 0.6 to 1.1 cases. However, rates for African Americans varied due to the small numbers of IBC cases. The twofold increase in IBC incidence was higher than that observed for non-IBC during the same period (27% for African Americans and 25% for whites). IBC patients were significantly younger at diagnosis than non-IBC patients; and among both IBC and non-IBC patients, African Americans were younger than whites. Overall survival was significantly worse for IBC patients than for non-IBC patients and for African Americans than for whites. Among whites, 3-year survival improved more for IBC patients than for non-IBC patients between 1975-1979 and 1988-1992, increasing from 32% to 42% for IBC patients (P=0.0001) and from 80% to 85% for non-IBC patients (P=0.0001). CONCLUSIONS: The disparities observed in incidence trends and age at diagnosis, particularly according to race, highlight the need for further investigation of the differences between IBC and non-IBC incidence.  相似文献   
62.
The muscle weakness in myasthenia gravis (MG) is caused by heterogeneous high-affinity IgG autoantibodies to the nicotinic acetylcholine receptor (AChR), a complex ion channel glycoprotein. These antibodies are clearly responsible for reducing AChR numbers at the neuromuscular junction in myasthenia; however, the origins, diversity, specificity and pathogenicity of individual antibodies have not yet been established. We have cloned and characterized four different AChR-specific Fab from an MG patient's thymus by screening an IgG1/kappa gene combinatorial lambda phage library with soluble human AChR labeled with [125I] alpha-bungarotoxin. Unlike most previously cloned human antibodies, all four Fab immunoprecipitated soluble human muscle AChR. Two Fab strongly inhibited binding of mAb to the main immunogenic region on the alpha subunits and one Fab bound to an epitope on the fetal-specific gamma subunit. In sensitivity and fine specificity, these Fab resembled the anti-AChR antibodies found in many MG patients, including the donor. The closest germline counterparts for their heavy chains were in VH families 1, 3 and 4; however, there were many differences consistent with an antigen-driven response of diverse B cell clones. The combinatorial approach holds promise for further analysis of human autoantibodies.  相似文献   
63.
The advance of the Internet in the past decade has radically changed the way people communicate and col- laborate with each other. Physical distance is no more a barrier in online social networks, but cultural differences (at the individual, community, as well as societal levels) still govern human-human interactions and must be con- sidered and leveraged in the online world. The rapid de-ployment of high-speed Internet allows humans to interact using a rich set of multimedia data such as texts, pictures, and videos. This position paper proposes to define a new research area called ’connected multimedia’, which is the study of a collection of research issues of the super-area social media that receive little attention in the literature. By connected multimedia, we mean the study of the social and technical interactions among users, multimedia data, and devices across cultures and explicitly exploiting the cultural differences. We justify why it is necessary to bring attention to this new research area and what benefits of this new research area may bring to the broader scientific research community and the humanity.  相似文献   
64.
Eighty beef crossbred steers with an average weight of 493 kg (4·66 kg SD) were allocated at random to one of five treatments to assess the effects of withholding feed and water on carcass shrinkage and meat quality. The five treatments were: slaughter from the feedlot (T1); and 12, 24, 36 and 48 h periods without feed and water prior to slaughter (T2-5).Weights were taken of the live animal and the carcass to monitor shrinkage along with relevant meat quality measurements. There were no treatment differences (P > 0·05) in initial farm weight, but plant weight shrinkage increased from 31gkg(-1) for T1 to 106 g kg(-1) for T5. Warm carcass weight decreased (P < 0·05) from 278·8 kg for T1, to 270·7 kg for T3 and 261·9 kg for T5. Liver, alimentary tract components, hide and head decreased as a proportion of farm weight as time without feed and water increased. Muscle pH at 6 days post mortem was increased (P < 0·05) in T3-5 compared to T1, with the result that muscle colour became darker, and steaks had less drip loss. Shear values increased (P < 0·05) from 6·3 kg in T1 to 7·7 kg in T4 and T5 indicating an increase in muscle toughness as time without feed and water increased. It was concluded that steers lose live weight rapidly within the first 24 h without feed and water, and that these relatively short periods of time (24 h) can have detrimental effects on carcass shrinkage and muscle quality.  相似文献   
65.
Fibrosis is a hallmark of adverse cardiac remodeling, which promotes heart failure, but it is also an essential repair mechanism to prevent cardiac rupture, signifying the importance of appropriate regulation of this process. In the remodeling heart, cardiac fibroblasts (CFs) differentiate into myofibroblasts (MyoFB), which are the key mediators of the fibrotic response. Additionally, cardiomyocytes are involved by providing pro-fibrotic cues. Nuclear receptor Nur77 is known to reduce cardiac hypertrophy and associated fibrosis; however, the exact function of Nur77 in the fibrotic response is yet unknown. Here, we show that Nur77-deficient mice exhibit severe myocardial wall thinning, rupture and reduced collagen fiber density after myocardial infarction and chronic isoproterenol (ISO) infusion. Upon Nur77 knockdown in cultured rat CFs, expression of MyoFB markers and extracellular matrix proteins is reduced after stimulation with ISO or transforming growth factor–β (TGF-β). Accordingly, Nur77-depleted CFs produce less collagen and exhibit diminished proliferation and wound closure capacity. Interestingly, Nur77 knockdown in neonatal rat cardiomyocytes results in increased paracrine induction of MyoFB differentiation, which was blocked by TGF-β receptor antagonism. Taken together, Nur77-mediated regulation involves CF-intrinsic promotion of CF-to-MyoFB transition and inhibition of cardiomyocyte-driven paracrine TGF-β-mediated MyoFB differentiation. As such, Nur77 provides distinct, cell-specific regulation of cardiac fibrosis.  相似文献   
66.
The mechanisms underlying the transport of leptin into the brain are still largely unclear. While the leptin receptor has been implicated in the transport process, recent evidence has suggested an additional role of LRP2 (megalin). To evaluate the function of LRP2 for leptin transport across the blood-brain barrier (BBB), we developed a novel leptin-luciferase fusion protein (pLG), which stimulated leptin signaling and was transported in an in vitro BBB model based on porcine endothelial cells. The LRP inhibitor RAP did not affect leptin transport, arguing against a role of LRP2. In line with this, the selective deletion of LRP2 in brain endothelial cells and epithelial cells of the choroid plexus did not influence bodyweight, body composition, food intake, or energy expenditure of mice. These findings suggest that LRP2 at the BBB is not involved in the transport of leptin into the brain, nor in the development of obesity as has previously been described.  相似文献   
67.
This paper introduces Voronoi squared distance minimization (VSDM), an algorithm that fits a surface to an input mesh. VSDM minimizes an objective function that corresponds to a Voronoi-based approximation of the overall squared distance function between the surface and the input mesh (SDM). This objective function is a generalization of the one minimized by centroidal Voronoi tessellation, and can be minimized by a quasi-Newton solver. VSDM naturally adapts the orientation of the mesh elements to best approximate the input, without estimating any differential quantities. Therefore, it can be applied to triangle soups or surfaces with degenerate triangles, topological noise and sharp features. Applications of fitting quad meshes and polynomial surfaces to input triangular meshes are demonstrated.  相似文献   
68.
Cavities in the hydrophobic core of the neutral protease ofBacillus stearothermophilus were analyzed using a threedimensionalmodel that was inferred from the crystal structure of thermolysin,the highly homologous neutral protease of B.thermoproteolyticus(85% sequence identity). Site–directed mutagenesis wasused to fill some of these cavities, thereby improving hydrophobicpacking in the protein interior. The mutations had small effectson the thermostability, even after drastic changes, such asLeu284Trp and Met168Trp. The effects on T50, the temperatureat which 50% of the enzyme is irreversibly inactivated in 30min, ranged from 0.0 to +0.4°C. These results can be explainedby assuming that the mutations have positive and negative structuraleffects of approximately the same magnitude. Alternatively,it could be envisaged that the local unfolding steps, whichrender the enzyme susceptible towards autolysis and which arerate limiting in the process of thermal inactivation, are onlyslightly affected by alterations in the hydrophobic core.  相似文献   
69.
In PSA Peugeot Citroen factories, high precision requirements of workstations make them being manual. One of the main goal of the car manufacturer is to minimize the pain of workers while maintaining high efficiency of production lines. Consequently, assisting operators with an exoskeleton is a potential solution for improving ergonomics of painful workstations while respecting industrial constraints. To determine ergonomic performances of an exoskeleton, human joint angles and torques, ground reaction forces, and duration of operations are analysed for eight subjects performing a representative screwing task. Experiments were performed using ABLE upper-limb exoskeleton, developed by the French Atomic Energy Commission (CEA), which has the functionality to compensate arm and tools loads. Results show a clear reduction of the sum of the joints torques, up to 38.9%, given by ABLE supply and invite to make concrete the use of exoskeletons in car assembly lines.  相似文献   
70.
This study, which deals with the distribution of hydrocarbons in seven types of rabbit tissues, was done for the purpose of providing information that might help shed light on the biological relevance of the hydrocarbons in mammalian metabolism. Liver, kidneys, brain, spleen, skeletal muscle, perinephric adipose, and a sample of blood serum were collected from a single animal for analysis of their hydrocarbon composition. The analytical methodology consisted of solvent extraction, saponification (adipose), elution chromatography on hydrated alumina, and combined gas chromatography-mass spectrometry. Hydrocarbons were detected in all of the tissues examined at concentrations estimated to range from 0.1 to 0.01% of the total lipid extracted. Three quite distinct distribution modes were recognized. The bulk of the identified components consisted of normal, saturated, nonterpenoid hydrocarbons in the C16 to C33 range. Squalene, phytene, phytadiene, and pristane were the only terpenoids detected. Nonterepenoid branched (iso andanteiso) hydrocarbons were identified unequivocally and in significant amounts in the muscle only. The adipose was the only tissue which was relatively rich in monoalkenes, and its overall hydrocarbon composition closely resembled that of the feed. The results of the study are not consistent with metabolic inertness. The observed qualitative and quantitative differences might reflect function and metabolic activities of the individual organs in a way yet to be elucidated. Presented in part at the AOCS Spring Meeting, New Orleans, April, 1976.  相似文献   
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