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排序方式: 共有624条查询结果,搜索用时 15 毫秒
51.
52.
Occult malignant breast lesions in 114 patients: relationship to age and the presence of microcalcifications 总被引:2,自引:0,他引:2
Hermann G; Janus C; Schwartz IS; Papatestas A; Hermann DG; Rabinowitz JG 《Radiology》1988,169(2):321-324
This study evaluates the mammographic findings in 352 patients, aged 30-85 years, who underwent spot localization and biopsy for evaluation of nonpalpable breast abnormalities. Malignancy was found at biopsy in 114 cases. The mammographic appearance (specifically, whether grouped microcalcifications, mass, or both were present) was correlated with patient age and histologic findings (specifically, whether the pathologic changes were infiltrating or noninfiltrating in nature). The prevalence of malignant conditions increased directly with age. The presence of grouped microcalcifications as the sole indicator of malignancy was seen in 100% (seven of seven) of the patients in the 30-39-year age group, 64% (18 of 28) in the 40-49-year age group, 37% (11 of 30) in the 50-59-year age group, 30% (seven of 23) in the 60-69-year age group, and 23% (six of 26) in the 70-85-year age group. Of the 49 tumors that were manifested solely as microcalcifications, 34 (69%) were noninfiltrating. The finding of grouped microcalcifications should be aggressively investigated, since it may indicate noninfiltrating carcinoma in an early stage, when the potential for cure is greatest. 相似文献
53.
Surgical approach to giant intracranial aneurysms. Operative experience with 80 cases. 总被引:3,自引:0,他引:3
The authors report experience with the surgical management of 80 giant intracranial aneurysms (greater than 2.5 cm in diameter) during a 10-year period in which they performed 594 operations for aneurysms. The overall incidence of giant aneurysms was 13% but varied according to location: 20% of aneurysms of the internal carotid artery (ICA); 13% of middle cerebral artery (MCA) aneurysms; 1% of anterior cerebral artery (ACA) aneurysms; 15% of aneurysms of the basilar artery caput (BAC); and 18% of vertebrobasilar trunk (VB) aneurysms. Twenty-five patients had a subarachnoid hemorrhage (SAH), 49 had mass effect from the aneurysm, and six had ischemic events. There was no apparent difference in results related to the presence or absence of an SAH. Poor results were attributable to the operation except in the two cases of ACA aneurysm in which preexisting dementia persisted. Mortality was 4% and morbidity was 14%, varying from a combined low morbidity-mortality of 8% for ICA lesions to a high to 50% for BAC aneurysms. During the period of the study, different techniques were developed in an attempt to lower the risks of surgery. Ultimately ICA aneurysms were monitored with cerebral blood flow measurements and electroencephalography before and after temporary ICA ligation, then approached following resection of the anterior clinoid or treated with bypass in combination with ICA ligation. Aneurysms of the MCA were either opened during temporary MCA occlusion or resected in combination with a bypass procedure. Bypass grafts and circulatory arrest with extracorporeal circulation may have a role in giant aneurysms of the posterior circulation. 相似文献
54.
Does Physical Activity in Adolescence Have Site‐Specific and Sex‐Specific Benefits on Young Adult Bone Size,Content, and Estimated Strength? 下载免费PDF全文
Rachel L Duckham Adam DG Baxter‐Jones James D Johnston Hassanali Vatanparast David Cooper Saija Kontulainen 《Journal of bone and mineral research》2014,29(2):479-486
The long‐term benefits of habitual physical activity during adolescence on adult bone structure and strength are poorly understood. We investigated whether physically active adolescents had greater bone size, density, content, and estimated bone strength in young adulthood when compared to their peers who were inactive during adolescence. Peripheral quantitative computed tomography (pQCT) was used to measure the tibia and radius of 122 (73 females) participants (age mean ± SD, 29.3 ± 2.3 years) of the Saskatchewan Pediatric Bone Mineral Accrual Study (PBMAS). Total bone area (ToA), cortical density (CoD), cortical area (CoA), cortical content (CoC), and estimated bone strength in torsion (SSIp) and muscle area (MuA) were measured at the diaphyses (66% tibia and 65% radius). Total density (ToD), trabecular density (TrD), trabecular content (TrC), and estimated bone strength in compression (BSIc) were measured at the distal ends (4%). Participants were grouped by their adolescent physical activity (PA) levels (inactive, average, and active) based on mean PA Z‐scores obtained from serial questionnaire assessments completed during adolescence. We compared adult bone outcomes across adolescent PA groups in each sex using analysis of covariance followed by post hoc pairwise comparisons with Bonferroni adjustments. When adjusted for adult height, MuA, and PA, adult males who were more physically active than their peers in adolescence had 13% greater adjusted torsional bone strength (SSIp, p < 0.05) and 10% greater adjusted ToA (p < 0.05) at the tibia diaphysis. Females who were more active in adolescence had 10% larger adjusted CoA (p < 0.05), 12% greater adjusted CoC (p < 0.05) at the tibia diaphysis, and 3% greater adjusted TrC (p < 0.05) at the distal tibia when compared to their inactive peers. Benefits to tibia bone size, content, and strength in those who were more active during adolescence seemed to persist into young adulthood, with greater ToA and SSIp in males, and greater CoA, CoC, and TrC in females. © 2014 American Society for Bone and Mineral Research. 相似文献
55.
Purpose: To investigate the hemodynamic changes in patients with acute cerebral stroke by perfusion MRI.
Materials and methods: In 12 patients with acute stroke in the territory of the middle cerebral artery, perfusion MRI was performed. Peak time,
mean transit time, regional cerebral blood volume and regional cerebral blood flow were calculated in the infarction, the
peri-infarction area and the contralateral hemisphere.
Results: In the infarction the mean blood flow was 29 ml/100 g/min, compared to about 40 ml/100 g/min in the peri-infarction area
and the contralateral hemisphere. In two patients increased cortical blood flow was found in the infarction due to luxury
perfusion. The cerebral blood volume was reduced in the infarction, but significantly increased, to 7.3 ml/100 g, in the peri-infarction
tissue.
Conclusion: Perfusion MRI allows one to differentiate various patterns of perfusion disorders in patients with acute cerebral stroke.
The resulting data may be helpful in describing the pathophysiologic mechanisms of compensation.
相似文献
56.
57.
Linkage of a familial platelet disorder with a propensity to develop myeloid malignancies to human chromosome 21q22.1-22.2 总被引:2,自引:4,他引:2
Ho CY; Otterud B; Legare RD; Varvil T; Saxena R; DeHart DB; Kohler SE; Aster JC; Dowton SB; Li FP; Leppert M; Gilliland DG 《Blood》1996,87(12):5218-5224
Linkage analysis was performed on a large pedigree with an autosomal dominant platelet disorder and a striking propensity in affected family members to develop hematologic malignancy, predominantly acute myelogenous leukemia. We report the linkage of the autosomal dominant platelet disorder to markers on chromosome 21q22. Four genetic markers completely cosegregate with the trait and yield maximum logarithm of difference scores ranging from 4.9 to 10.5 (theta = .001). Two flanking markers, D21S1265 and D21S167, define a critical region for the disease locus of 15.2 centimorgan. Further analysis of this locus may identify a gene product that affects platelet production and function and contributes to the molecular evolution of hematologic malignancy. 相似文献
58.
Elevation of serum cystathionine levels in patients with cobalamin and folate deficiency 总被引:14,自引:0,他引:14
Homocysteine can be methylated to form methionine by the cobalamin- (Cbl) and folate-dependent enzyme, methionine synthase; serum levels of total homocysteine are elevated in greater than 95% of patients with either Cbl or folate deficiency. Homocysteine can also condense with serine to form cystathionine in a pyridoxal phosphate-dependent reaction catalyzed by cystathionine beta-synthase. Cystathionine is subsequently cleaved to cysteine and alpha-ketobutyrate by the pyridoxal phosphate-dependent enzyme gamma-cystathionase. To assess levels of cystathionine in Cbl and folate deficiency, we developed a new capillary gas chromatographic-mass spectrometric assay and measured cystathionine in the serum of normal subjects and patients with clinically confirmed deficiencies of these vitamins. The normal range for serum cystathionine was 65 to 301 nmol/L (median = 126 nmol/L) for 50 normal blood donors. In 30 patients with clinically confirmed Cbl deficiency, values for cystathionine ranged from 208 nmol/L to 2,920 nmol/L (median = 816 nmol/L) and 26 (87%) had levels above the normal range. In 20 patients with clinically confirmed folate deficiency, cystathionine concentrations ranged from 138 nmol/L to 4,150 nmol/L (median = 1,560 nmol/L) and 19 (95%) had values above the normal range. Five homozygotes for cystathionine beta-synthase deficiency had high values for serum-total homocysteine and low or low-normal values for serum cystathionine that ranged from 30 nmol/L to 114 nmol/L even though they were on treatment with pyridoxine and had partially responded. One patient with a defect in the synthesis of 5-CH3- tetrahydrofolate and five patients with defects in the synthesis of CH3- Cbl had high values for serum-total homocysteine and high values for cystathionine that ranged from 311 nmol/L to 1,500 nmol/L even though they were on treatment with folic acid and Cbl, respectively, and had partially responded. We conclude that levels of cystathionine are evaluated in the serum of most patients with Cbl and folate deficiency and that they are useful in the differential diagnosis of an elevated serum-total homocysteine level. 相似文献
59.
60.
Congenital heart lesions involving the right ventricular outflow tract (RVOT) are a common problem in paediatric cardiology. These patients need multiple surgical interventions in the form of valved conduits over a lifetime. Surgical re-valvulation was the standard treatment option until the introduction of percutaneous pulmonary valves over a decade ago. These valves can be used to prolong the lifespan of conduits and reduce the number of re-operations. The Melody® valve (Medtronic, Minneapolis, MN, USA) was introduced as the first dedicated percutaneous pulmonary valve. Percutaneous pulmonary valves can be implanted successfully and have the advantage of short hospitalisations. We describe the first three Melody® valve implantations in Africa. 相似文献