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排序方式: 共有168条查询结果,搜索用时 78 毫秒
41.
42.
JB Parentes-Vieira PV Lopes-Costa CG Pires AR dos Santos JD Pereira-Filho BB da Silva 《International Seminars in Surgical Oncology : ISSO》2007,4(1):22
Background
The objective of this study was to evaluate angiogenesis according to CD34 antigen expression in estrogen receptor (ER)-positive and negative breast carcinomas.Methods
This study comprised 64 cases of infiltrating ductal carcinoma in postmenopausal women divided into two groups: Group A: ER-positive, n = 35; and Group B: ER-negative, n = 29. The anti-CD34 monoclonal antibody was used as a marker for endothelial cells. Microvessel count was carried out in 10 fields per slide using a 40× objective lens (magnification 400×). Statistical analysis of the data was performed using Student's t-test (p < 0.05).Results
The mean number of vessels stained with the anti-CD34 antibody in the estrogen receptor-positive and negative tumors was 23.51 ± 1.15 and 40.24 ± 0.42, respectively. The number of microvessels was significantly greater in the estrogen receptor-negative tumors (p < 0.001).Conclusion
ER-negative tumors have significantly greater CD34 antigen expression compared to ER-positive tumors.43.
44.
Systemic corticosteroid therapy has been used to treat hemangiomas for 30 years; yet, there are no studies of possible complications. We reviewed the database of the Vascular Anomalies Center at the Boston Children's Hospital and gathered information on short- and long-term side effects in children who were given systemic corticosteroids for problematic hemangiomas. In addition, a questionnaire regarding early and late consequences was sent to the families of children who were treated with corticosteroids from 1983 to 1997. Of 300 patients with hemangiomas, 80 children were identified as having received a full course of systemic corticosteroids for problematic tumors. Complete data were collected on 62 of these children. The response rate to the questionnaire was 78 percent (n = 62 of 80). The initial dose of corticosteroid varied from 2 to 3 mg/kg/ day. Duration of therapy ranged from 2 to 21 months (mean, 7.9 months; median, 6.5 months). The follow-up interval from the cessation of therapy ranged from 6 months to 15 years (mean, 4 years; median, 3 years). Short-term complications included cushingoid facies (n = 44; 71 percent), personality changes (n = 18; 29 percent), gastric irritation (n = 13; 21 percent), fungal (oral or perineal) infection (n = 4; 6 percent), and diminished gain of height (n = 22; 35 percent) and weight (n = 26; 42 percent). A total of 91 percent of children who had diminished gain of height (n = 20) returned to their pretreatment growth curve for height by 24 months of age. One child, who was treated at another institution with a dose of 20 mg/kg/day for 6.5 months that was slowly tapered over 18 months, was petite 6 years after ending therapy. Another child treated with an initial dose of 2 mg/kg/day for 5 months was smaller than predicted at the age of 6 years, but she was born prematurely and was on ventilatory support for respiratory distress. Three children treated with the standard dose and duration were at a low percentile for weight 4, 5, and 10 years after the cessation of therapy. Statistical analysis showed a correlation between diminished gain of height with duration of therapy and age at initiation of treatment. One child had corticosteroid myopathy that resolved with cessation of therapy. We found no evidence for immunologic suppression, i.e., there was no increase in the number of bacterial infections during corticosteroid administration. In conclusion, systemic corticosteroids can be safely given to treat endangering hemangiomas in infants at doses of 2 to 3 mg/kg/day, which are slowly tapered and stopped before the age of 1 year. Short-term side effects were minor and transient, and no serious long-term complications occurred. 相似文献
45.
Vasoactive exposures, vascular events, and hemifacial microsomia 总被引:9,自引:0,他引:9
Werler MM Sheehan JE Hayes C Mitchell AA Mulliken JB 《Birth defects research. Part A, Clinical and molecular teratology》2004,70(6):389-395
BACKGROUND: Based on experimental evidence and clinical observations, hemifacial microsomia (HFM) is one of several structural anomalies that are postulated to result from vascular disruption. We collected data in a case-control study to identify whether vasoactive exposures or vascular events during early pregnancy affect the risk of HFM. METHODS: Cases with a diagnosis of HFM were identified at craniofacial centers in 26 cities across the United States and Canada, from 1996 to 2002. Controls were matched to cases by age and pediatrician practice. Mothers of 230 cases and 678 controls were interviewed about pregnancy events and exposures. Case and control mothers were compared for early pregnancy use of vasoactive medications, cigarettes, and alcohol; singleton or multiple gestation; and diabetes, hypertension, or vaginal bleeding in the first half of pregnancy. RESULTS: Odds ratios (ORs) were significantly increased for vasoactive mediation use (OR, 1.9 overall; OR, 4.2 among smokers), multiple gestations (OR, 10.5), and diabetes (OR, 6.0). Vaginal bleeding in the second trimester and heavy alcohol intake were associated with increased risks, but the estimates were based on small numbers and, therefore, are unstable. No associations were observed for cigarette smoking without vasoactive medication use, hypertension, and vaginal bleeding in the first trimester. CONCLUSIONS: The increased risks of HFM associated with vasoactive medication use, multiple gestations, diabetes, and second trimester vaginal bleeding appear collectively to support the hypothesis that vascular disruption is one etiology for HFM, because each of these factors is related to effects on blood vessels. 相似文献
46.
Exons 5 and 7 of the fibroblast growth factor receptor 2 (FGFR2) gene code for immunoglobulin-like domain III (IgIII) and
for the region connecting the second and the third Ig domain of the receptor. Numerous mutations in these two exons have been
shown to cause various craniosynostotic syndromes. Here, we describe three previously unrecognized mutations at amino acid
positions 276, 301, and 314, in one nonspecific craniosynostosis and in two Crouzon patients. We also present a polypeptide
model of IgIII of FGFR2. The known mutations involve five distinct structural elements of the receptor. The changes within
these elements affect receptor function by various mechanisms, including altered dimerization, truncation, increased mobility
between Ig domains, disintegration of IgIII, and alteration of the ligand-binding site.
Received: 30 June 1997 / Accepted: 31 October 1997 相似文献
47.
Substitution bias, rapid saturation, and the use of mtDNA for nematode systematics 总被引:13,自引:0,他引:13
Only relatively recently have researchers turned to molecular methods for
nematode phylogeny reconstruction. Thus, we lack the extensive literature
on evolutionary patterns and phylogenetic usefulness of different DNA
regions for nematodes that exists for other taxa. Here, we examine the
usefulness of mtDNA for nematode phylogeny reconstruction and provide data
that can be used for a priori character weighting or for parameter
specification in models of sequence evolution. We estimated the
substitution pattern for the mitochondrial ND4 gene from intraspecific
comparisons in four species of parasitic nematodes from the family
Trichostrongylidae (38-50 sequences per species). The resulting pattern
suggests a strong mutational bias toward A and T, and a lower
transition/transversion ratio than is typically observed in other taxa. We
also present information on the relative rates of substitution at first,
second, and third codon positions and on relative rates of saturation of
different types of substitutions in comparisons ranging from intraspecific
to interordinal. Silent sites saturate extremely quickly, presumably owing
to the substitution bias and, perhaps, to an accelerated mutation rate.
Results emphasize the importance of using only the most closely related
sequences in order to infer patterns of substitution accurately for
nematodes or for other taxa having strongly composition-biased DNA. ND4
also shows high amino acid polymorphism at both the intra- and
interspecific levels, and in higher level comparisons, there is evidence of
saturation at variable amino acid sites. In general, we recommend using
mtDNA coding genes only for phylogenetics of relatively closely related
nematode species and, even then, using only nonsynonymous substitutions and
the more conserved mitochondrial genes (e.g., cytochrome oxidases). On the
other hand, the high substitution rate in genes such as ND4 should make
them excellent for population genetics studies, identifying cryptic
species, and resolving relationships among closely related congeners when
other markers show insufficient variation.
相似文献
48.
Phylogeny of the Drosophila saltans species group based on combined analysis of nuclear and mitochondrial DNA sequences 总被引:2,自引:0,他引:2
Nucleotide sequences from two nuclear loci, alcohol dehydrogenase and
internal transcribed spacer-1 of the nuclear ribosomal DNA repeats, and two
mitochondrial genes, cytochrome oxidase I and cytochrome oxidase II, were
determined from nine species in the Drosophila saltans species group. The
partition homogeneity test and partitioned Bremer support were used to
measure incongruence between phylogenetic hypotheses generated from
individual partitions. Individual loci were generally congruent with each
other and consistent with the previously proposed morphological hypothesis,
although they differed in level of resolution. Since extreme conflict
between partitions did not exist, the data were combined and analyzed
simultaneously. The total evidence method gave a more resolved and highly
supported phylogeny, as indicated by bootstrap proportions and decay
indices, than did any of the individual analyses. The cordata and elliptica
subgroups, considered to have diverged early in the history of the D.
saltans group, were sister taxa to the remainder of the saltans group. The
sturtevanti subgroup, represented by D. milleri and D. sturtevanti,
occupies an intermediate position in this phylogeny. The saltans and
parasaltans subgroups are sister clades and occupy the most recently
derived portion of the phylogeny. As with previous morphological studies,
phylogenetic relationships within the saltans subgroup were not
satisfactorily resolved by the molecular data.
相似文献
49.
Nucleotide sequence comparisons were used to investigate the evolution of P
transposable elements and the possibility that horizontal transfer has
played a role in their occurrence in natural populations of Drosophila and
other Diptera. The phylogeny of P elements was examined using published
sequences from eight dipteran taxa and a new, partial sequence from
Scaptomyza elmoi. The results from a number of different analyses are
highly consistent and reveal a P-element phylogeny that contradicts the
phylogeny of the species. At least three instances of horizontal transfer
are necessary to explain this incongruence, but other explanations cannot
be ruled out at this time.
相似文献
50.
Synchronous repair of bilateral complete cleft lip and nasal deformity requires conception of three-dimensional form and fourth-dimensional changes with growth, as distorted by the malformation. The aim is to obviate typical postoperative nasolabial stigmata. The strategy is to construct fast-growing features on a smaller scale and slow-growing features on a normal or slightly larger scale. In this study, intraoperative alterations in nasolabial dimensions were documented by anthropometry in 46 consecutive infants with bilateral complete cleft lip. These values were averaged and compared with measures from normal Caucasian infants at ages 0 to 5 months and 6 to 12 months. Nasal height (n-sn) and nasal width (al-al), both fast-growing features, were set smaller (88 percent and 96 percent, respectively) than those of age-matched normal infants. In contrast, the slow-growing features, nasal protrusion (sn-prn) and columellar length, were constructed longer than normal (130 percent and 167 percent, respectively). Because all labial features grow rapidly, they were made diminutive in this study, with the exception of central vermilion-mucosal height (median tubercle), which was purposively made full. These maneuvers resulted in a normal, average overall upper-lip height (sn-sto). Two technical refinements also are described: (1) construction of deepithelialized bands flanking the philtral flap to improve surface contour; and (2) positioning and fixation of the dislocated alar cartilages, performed entirely through superiomedial nostril rim incisions. 相似文献