933 resultados para Abnormal Subgroups
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AIMS: To compare the performance of ultrasound elastography with conventional ultrasound in the assessment of axillary lymph nodes in suspected breast cancer and whether ultrasound elastography as an adjunct to conventional ultrasound can increase the sensitivity of conventional ultrasound used alone. MATERIALS AND METHODS: Fifty symptomatic women with a sonographic suspicion for breast cancer underwent ultrasound elastography of the ipsilateral axilla concurrent with conventional ultrasound being performed as part of triple assessment. Elastograms were visually scored, strain measurements calculated and node area and perimeter measurements taken. Theoretical biopsy cut points were selected. The sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) were calculated and receiver operating characteristic (ROC) analysis was performed and compared for elastograms and conventional ultrasound images with surgical histology as the reference standard. RESULTS: The mean age of the women was 57 years. Twenty-nine out of 50 of the nodes were histologically negative on surgical histology and 21 were positive. The sensitivity, specificity, PPV, and NPV for conventional ultrasound were 76, 78, 70, and 81%, respectively; 90, 86, 83, and 93%, respectively, for visual ultrasound elastography; and for strain scoring, 100, 48, 58 and 100%, respectively. There was no significant difference between any of the node measurements CONCLUSIONS: Initial experience with ultrasound elastography of axillary lymph nodes, showed that it is more sensitive than conventional ultrasound in detecting abnormal nodes in the axilla in cases of suspected breast cancer. The specificity remained acceptable and ultrasound elastography used as an adjunct to conventional ultrasound has the potential to improve the performance of conventional ultrasound alone.
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小G蛋白(small GTPases)是真核生物中广泛存在的一类调节各种生命活动的信号分子。根据结构与功能的不同,小G蛋白家族成员可分成五个亚家族,分别为Ras,Rab,Rho,Arf和Ran。五类小G蛋白通过其活化态(GTP结合态)和非活化态(GDP结合态)的相互转换行使着各种功能。Ras GTPases在酵母和哺乳动物中调节细胞增殖过程; Rho GTPases调控肌动蛋白重组过程,并参与MAP 激酶的细胞信号转导过程等; Rab GTPases和Arf GTPases分别在膜转运过程中起着不同的重要作用;而Ran GTPases则在核孔位置调节着蛋白和RNA分子的运输过程。 小G蛋白附属蛋白调节着小G蛋白活化态与非活化态之间的转换,其中鸟核苷酸交换因子(guanine nucleotide exchange factors, GEFs)可以催化小G蛋白转换为GTP结合形式,即活化态;而GTPase 激活蛋白(GTPase-activating proteins, GAPs)和小G蛋白结合蛋白(small GTPases binding proteins)可以激活小G蛋白自身的水解活性,从而将其转变成非活化态形式。 相比其它小G蛋白,Ran GTPases及其附属蛋白在真核生物中的研究相对较少。已有的成果表明它们主要在核质运输过程中及对相应的信号转导途径起调节作用。而针对Ran GTPases及其附属蛋白在真核生物尤其是高等植物个体发育过程中的作用,目前报道还很少。 为了揭示Ran结合蛋白(Ran binding protein, RanBP)在植物发育过程中的作用,本文通过转基因手段对其功能进行 了研究。在此之前,本实验室已从小麦cDNA文库中成功克隆Ran结合蛋白基因:TaRanBP。该基因cDNA全长1035 bp,编码207个氨基酸。通过农杆菌介导叶圆片法,分别用正义、反义及TaRanBP与GFP融合蛋白等表达载体转化烟草,并成功获得转基因植株。亚细胞定位观察发现TaRanBP蛋白主要定位于细胞质内,尤其是在核膜附近富集。生理学和细胞学等方面的研究分析发现,TaRanBP基因在烟草个体发育过程中产生重要作用。过量表达TaRanBP基因的转基因植株在一定数量上表现出愈合的花冠筒上出现不同程度开裂,花冠筒上有附生舌状花瓣,及带有花瓣状颜 色的花萼等异常花表型。同时,转反义基因在一定程度上促进了转基因植株初生主根的生长(为对照烟草的2.3倍),而转正义基因烟草与对照烟草的初生主根长度差异不明显。用碘化丙锭(Propidium Iodide, PI)进行根部细胞染色。观察发现,不同的转基因烟草与对照烟草之间在根的各个不同形态区域的细胞大小差异不明显,推测根长的差异可能是由于整体细胞数目变化的原因导致。向重力性实验发现,转反义基因烟草幼苗较对照烟草的向重力性反应增加,而转正义基因的则表现为降低。激素吲哚乙酸(Indoleacetic Acid, IAA)的添加处理可以恢复转反义基因烟草的向重力性异常表型,而对转正义基因烟草几乎无影响。添加激动素(Kinetin, KT)的处理发现不同转基因烟草和对照烟草的向重力性均有减弱。观测后期,转正义基因的向重力敏感性较对照烟草得到恢复。测量不同转基因株系T1代幼苗鲜重,发现不同转基因烟草和对照烟草的幼苗鲜重动态变化在各个时间点有差异,且差异情况不尽相同。而不同转基因幼苗T1代幼苗可溶性蛋白含量较对照烟草有不同程度的下降。这种下降并没有影响转基因烟草的整体生长进程,开花期和结实情况与对照烟草相比也无明显变化。
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A model of graphite which is easy to comprehend and simple to implement for the simulation of scanning tunneling microscopy (STM) images is described. This model simulates the atomic density of graphite layers, which in turn correlates with the local density of states. The mechanism and construction of such a model is explained with all the necessary details which have not been explicitly reported before. This model is applied to the investigation of rippling fringes which have been experimentally observed on a superlattice, and it is found that the rippling fringes are not related to the superlattice itself. A superlattice with abnormal topmost layers interaction is simulated, and the result affirms the validity of the moiré rotation pattern assumption. The "odd-even" transition along the atomic rows of a superlattice is simulated, and the simulation result shows that when there is more than one rotated layer at the top, the "odd-even" transition will not be manifest. ©2005 The Japan Society of Applied Physics.
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Microcephaly (MCPH) genes are informative in understanding the genetics and evolution of human brain volume. MCPH1 and abnormal spindle-like MCPH associated (ASPM) are the two known MCPH causing genes that were suggested undergone recent positive selectio
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An association of the dopamine receptor D4 (DRD4) gene located on chromosome 11p15.5 and attention deficit/hyperactivity disorder (ADHD) has been demonstrated and replicated by multiple investigators. A specific allele [the 7-repeat of a 48-bp variable number of tandem repeats (VNTR) in exon 3] has been proposed as an etiological factor in attentional deficits manifested in some children diagnosed with this disorder. In the current study, we evaluated ADHD subgroups defined by the presence or absence of the 7-repeat allele of the DRD4 gene, using neuropsychological tests with reaction time measures designed to probe attentional networks with neuroanatomical foci in D4-rich brain regions. Despite the same severity of symptoms on parent and teacher ratings for the ADHD subgroups, the average reaction times of the 7-present subgroup showed normal speed and variability of response whereas the average reaction times of the 7-absent subgroup showed the expected abnormalities (slow and variable responses). This was opposite the primary prediction of the study. The 7-present subgroup seemed to be free of some of the neuropsychological abnormalities thought to characterize ADHD.
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The human D2 dopamine receptor gene (DRD2) plays a central role in the neuromodulation of appetitive behaviors and is implicated in having a possible role in susceptibility to alcoholism. We genotyped an SNP in DRD2 Exon 8 in 251 nonalcoholic, unrelated, healthy controls and 200 alcoholic Mexican Americans. The DRD2 haplotypes were analyzed using the Exon 8 genotype in combination with five other SNP genotypes, which were obtained from our previous study. The ancestral origins of the DRD2 polymorphisms have been determined by sequencing the homologous region in other higher primates. Twenty DRD2 haplotypes, defined as H1 to H20 based on their frequency from high to low, were obtained in this major minority population. The ancestral haplotype "I-132-G-C-G-A1" and two one-step mutation haplotypes were absent in our study population. The haplotype H1, "I-B1-T-C-A-A1", with the highest frequency in the population, is a three-step mutation from the ancestral form. The first five or eight major haplotypes make up 87% or 95% of the entire population, respectively. The prevalence of the haplotype H1+ (H1/H1 and H1/Hn genotypes) is significantly higher in alcoholics and alcoholic subgroups, including early onset drinkers and benders, than in their respective control groups. The Promoter -141C allele is in linkage disequilibrium (LD) with five other loci in the nonalcoholic group, but not in the alcoholic group. All of the other five loci are in LD in both the alcoholic and control groups. The DRD2 TaqI B allele is in complete LD with the allele located in intron 6. Five SNPs, Promoter -141C, TaqI B (or Intron 6), Exon 7, Exon 8, and TaqI A, are sufficient to define the DRD2 haplotypes in Mexican Americans. Our data indicate that the DRD2 haplotypes are associated with alcoholism in Mexican Americans. (c) 2005 Elsevier Inc. All rights reserved.
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Purkinje cell degeneration (pcd) mice are characterized by death of virtually all cerebellar Purkinje cells by postnatal day 30. In this study, we used DNA microarray analysis to investigate differences in gene expression between the brains of wild type and pcd mice on postnatal day 20, before the appearance of clear-cut phenotypic abnormalities. We identified 300 differentially expressed genes, most of which were involved in metabolic and physiological processes. Among the differentially expressed genes were several calcium binding proteins including calbindin -28k, paravalbumin, matrix gamma-carboxygluta mate protein and synaptotagamins 1 and 13, suggesting the involvement of abnormal Ca2+ signaling in the pcd phenotype.
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Eggs of P. monodon are classified into 5 different types on the basis of morphological criteria and hatching rates: A sub(1) eggs, which undergo normal development with 58% hatching rate; A sub(2) eggs, which show delayed and/or abnormal development with 32% hatching rate; B eggs, which are unfertilized and characterized by irregular cytoplasmic formation; C eggs, which are unfertilized and show no change in appearance; and D eggs, which are unfertilized and show extensive bacterial presence. The establishment of a highly linear relationship between percent A sub(1) eggs and hatching rate provides a useful tool to aid the hatchery technician in determining which spawnings to reject outright and which to rear through the larval and post-larval stages.
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Even though it generates healthy adults, nuclear transfer in mammals remains an inefficient process. Mainly attributed to abnormal reprograming of the donor chromatin, this inefficiency may also be caused at least partly by a specific effect of the clonin
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Studies were conducted to know the effects of alum on the histological changes of silver barb (Barbodes gonionotus) fry in the aquarium. The use of up to 0.5 g/L of alum for 120 hours as means of treatment of fish diseases is safe. At this level, no abnormal behavior and pathological alteration were observed in the organs of experimental fish. As the doses increased to 1.25 g/L and above (1.5 g/L), experimental fishes exhibited abnormal movement and with marked histopathological changes in the various organs. A dose of above 0.5 g/L should be strictly prohibited.
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Drug addiction is increasingly viewed as the expression of abnormal associative learning following repeated exposures to the drugs of abuse Previous I studies have demonstrated that the patterns of repetition such as frequency and spacing are important to many kinds of learning and memory retention We hypothesized that drug repetition pattern might affect the reward-related learning although the total doses of the drug were the same. In the present study, we tested morphine-induced place preference following either regular or irregular pattern of morphine pairing in rats Regular morphine group received morphine administration daily at a regular time with the same dose Irregular morphine groups received morphine administration either at the same time but irregular doses, irregular time but same dose, or irregular time and irregular doses. We found that rats, who received irregular morphine pairing, exhibited similar acquisition of peace preference but different preference retentions compared with regular morphine-treated rats after the same total dose of morphine Rats, who received morphine administration at the same time but irregular doses and at irregular time and irregular doses, showed rapid disruption of place preference than the regular morphine group. Rats, who received morphine at irregular time but the same dose, showed similar retention of place preference to regular morphine group Our results suggest that the pattern of drug pairing plays an important role in the retention of reward-related memory This study may provide new evidence to broaden our understanding of the development and maintenance of drug craving (C) 2009 Elsevier B V. All rights reserved
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Morphological assessment of sexually mature Rutilus frisii kutum Kamenskii 1901 caught from the rivers (Shirud, Khoshkrud, Sepidrud and Chelavand Rivers) flowing in the southwest Caspian Sea region was conducted and sperm volume, total sperm count and sperm concentration of abnormal sperms were determined after exposing the spawners to 60% herbicide butachlor (machete). Spawners under study were maintained in tanks (1000 l) at the Shahid Ansari Teleost Fish Hatchery and exposed to two different concentrations (25% and 75% of its LC50 value) of butachlor. Results obtained indicate that exposure to high butachlor toxicity (75% of its LC50 value) decreased sperm volume to 0.61 ± 0.42 cc in 2-3 year old fishes and to 0.55 ± 0.42 cc in fishes above 3 years of age, while that in fish exposed to low butachlor toxicity (25% of its LC50 value) decreased to 1.55 ± 0.42 cc in 2-3 year old fishes and to 1.28 ± 0.42 cc in fishes above 3 years of age. The sperm volume under normal conditions in R. frisii kutum is 4.6 ± 0.42 cc in 2-3 year olds and 4.58 ± 0.42 cc in fishes above 3 years of age. The total sperm count in R. frisii kutum is 39.74 ± 2.5 billion spermatozoa/cc in 2-3 year olds and 42.99 ± 2.5 billion spermatozoa/cc in fishes above 3 years of age. When exposed to high butachlor toxicity, total sperm count dropped to 16.92 ± 2.5 billion spermatozoa/cc in 2-3 year olds and to 15.98 ± 2.5 billion spermatozoa/cc in fishes above 3 years of age. Similarly total sperm count in R. frisii kutum exposed to low butachlor toxicity was recorded as 23.6 ± 2.5 billion spermatozoa/cc in 2-3 year olds and 29.4 ± 2.5 billion spermatozoa/cc in fishes above 3 years of age. Under normal conditions, on the basis of morphology, spermatozoa showed only 10 ± 1.92% of abnormal sperms. The number of abnormal sperms increased by 28.6 ± 1.92% in fishes exposed to high butachlor toxicity, while that in fishes exposed to low butachlor toxicity increased by 19.7 ± 1.92% in 2-3 year olds and 16.6 ± 19.2% in fishes above 3 years of age. It is evident from the results obtained that increase in level of pollution caused a decrease in sperm volume but an increase in the percentage of abnormal sperms. Results obtained indicate that exposure to high butachlor toxicity (75% of its LC50 value) decreased testostron hormone to 0.31 ± 0.22 ng/ml in high butachlor toxicity, and to 0.45 ± 0.22 ng/ml in low butachlor toxicity (25% of its LC50 value). Testostron hormone dropped to 0.53 ± 0.22 ng/ml in 2-3 year olds and to 0.79 ± 0.22ng/ in fishes above 3 years of age. The testostron hormone under normal conditions in R. frisii kutum is 2.7 ± 0.22 ng/ml. It is evident from the results obtained that increase in level of pollution caused a decrease in testostron hormone
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Phylogenetic relationships among 15 species of wood mice (genus Apodemus) were reconstructed to explore some long-standing taxonomic problems. The results provided support for the monophyly of the genus Apodemus, but could not reject the hypothesis of paraphyly for this genus. Our data divided the 15 species into four major groups: (1) the Sylvaemus group (A. sylvaticus, A. flavicollis, A. alpicola, and A. uralensis), (2) the Apodemus group (A. peninsulae, A. chevreri, A. agrarius, A. speciosus, A. draco, A. ilex, A. semotus, A. latronum, and A. mystacinus), (3) A. argenteus, and (4) A. gurkha. Our results also suggested that orestes should be a valid subspecies of A. draco rather than an independent species; in contrast, A. ilex from Yunnan may be regarded as a separate species rather than a synonym of orestes or draco. The species level status of A. latronum, tscherga as synonyms of A. uralensis, and A. chevrieri as a valid species and the closest sibling species of A. agrarius were further corroborated by our data. Applying a molecular clock with the divergences of Mus and Rattus set at 12 million years ago (Mya) as a calibration point, it was estimated that five old lineages (A. mystacinus and four major groups above) diverged in the late Miocene (7.82-12.74 Mya). Then the Apodemus group (excluding A. mystacinus) split into two subgroups: agrarius and draco, at about 7.17-9.95 Mya. Four species of the Sylvaemus group were estimated to diverge at about 2.92-5.21 Mya. The Hengduan Mountains Region was hypothesized to have played important roles in Apodemus evolutionary histories since the Pleistocene. (C) 2004 Elsevier Inc. All rights reserved.
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Avalanche multiplication has been one of the major destructive failure mechanisms in IGBTs; in order to avoid operating an IGBT under abnormal conditions, it is desirable to develop peripheral protecting circuits monolithically integrated without compromising the operation and performance of the IGBT. In this paper, a monolithically integrated avalanche diode (D av) for 600V Trench IGBT over-voltage protection is proposed. The mix-mode transient simulation proves the clamping capability of the D av when the IGBT is experiencing over-voltage stress in unclamped inductive switching (UIS) test. The spread of avalanche energy, which prevents hot-spot formation, through the help of the avalanche diode feeding back a large fraction of the avalanche current to a gate resistance (R G) is also explained. © 2011 IEEE.
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The taxonomy of the douc and snub-nosed langurs has changed several times during the 20th century. The controversy over the systematic position of these animals has been due in part to difficulties in studying them: both the doucs and the snub-nosed langurs are rare in the wild and are generally poorly represented in institutional collections. This review is based on a detailed examination of relatively large numbers of specimens of most of the species of langurs concerned. An attempt was made to draw upon as many types of information as were available in order to make an assessment of the phyletic relationships between the langur species under discussion. Toward this end, quantitative and qualitative features of the skeleton, specific features of visceral anatomy and characteristics of the pelage were utilized. The final data matrix comprised 178 characters. The matrix was analyzed using the program Hennig86. The results of the analysis support the following conclusions: (1) that the douc and snub-nosed langurs are generically distinct and should be referred to as species of Pygathrix and Rhinopithecus, respectively; (2) that the Tonkin snub-nosed langur be placed in its own subgenus as Rhinopithecus (Presbytiscus) avunculus and that the Chinese snub-nosed langur thus be placed in the subgenus Rhinopithecus (Rhinopithecus); (3) that four extant species of Rhinopithecus be recognized: R. (Rhinopithecus) roxellana Milne Edwards, 1870; R. (Rhinopithecus) bieti Milne Edwards, 1897; R. (Rhinopithecus) brelichi Thomas, 1903, and R. (Presbytiscus) avunculus Dollman, 1912; (4) that the Chinese snub-nosed langurs fall into northern and southern subgroups divided by the Yangtze river; (5) that R. lantianensis Hu and Qi, 1978, is a valid fossil species, and (6) the precise affinities and taxonomic status of the fossil species R. tingianus Matthew and Granger, 1923, are unclear because the type specimen is a subadult.