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61.
62.
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.  相似文献   
63.
Enantiomerically pure hexahydroquinolinones of the structural type 9 were prepared by a variation of the Hantzsch synthesis in which an optically active acetoacetate served as a chiral auxiliary reagent. Determinations of the de and ee values are described. The absolute configurations of the optically pure products were characterized by single-crystal X-ray analysis. The antipodes 9a and 9b exhibited calcium antagonistic activities on smooth musculature; the (S)-(-)-enantiomer 9b was the more potent compound with regard to the EC50 values which differed by a factor of 100; the intrinsic activity of 9b was 1.2, compared with a value of 0.54 for 9a. On the other hand, R-(+)-9a exerted positive inotropic effects on electrically stimulated atria. The cause of these effects is discussed.  相似文献   
64.
1.5 tesla magnetic resonance imaging of acute spinal trauma   总被引:2,自引:0,他引:2  
Fifty patients with spinal injury above L2 were studied with MRI; forty-two had initial and followup studies permitting correlation of MRI abnormalities with neurologic improvement. Two discrete patterns of MRI abnormality were identified, presumably representing cord hemorrhage and edema respectively. A third pattern appeared to represent a mixed type of injury. The correlation between the MRI patterns of cord injury and neurologic recovery was excellent. The ability of MRI to demonstrate and characterize acute cord injury appears to exceed that of other diagnostic techniques.  相似文献   
65.
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.  相似文献   
66.
The frequency and clinical significance of platelet/fibrin microemboli in the microcirculation were investigated in 24 patients whose deaths (before and during hospital admission) were associated with acute myocardial infarction. An acute coronary thrombus was present in all the hearts. In nine hearts an acute thrombus was found in more than one major epicardial coronary artery. A total of 35 acute thrombi were found in the 24 hearts. Platelet/fibrin microemboli were found in 19 (79%) hearts. Eighteen patients died in hospital. The hearts of 16 of these cases showed microemboli; 16 had important arrhythmias or various forms of heart block; 13 showed acute pathological changes in the conduction system. Fourteen of the deaths in hospital were primarily the result of cardiogenic shock and four were primarily caused by arrhythmia. Six of the deaths that occurred before admission to hospital were regarded as being arrhythmic in origin. Three of these showed microemboli and the other three had acute pathological changes in the conduction system. Microemboli were found in two (24%) of 12 control hearts. Coronary thrombosis was found in most deaths caused by acute myocardial infarction and platelet/fibrin microemboli were present in the majority of such hearts. These may arise from the coronary thrombus in the larger upstream vessel supplying the microcirculation.  相似文献   
67.
Out of 29 patients with right-sided infective endocarditis 13 had associated congenital heart disease and none was a drug addict. Staphylococcus aureus was the commonest organism isolated. The tricuspid valve was infected twice as commonly as the pulmonary valve. Only 11 out of the 29 patients had valvular infection potentially amenable to surgical therapy at the time of death. Ring abscesses were present in 10 patients.  相似文献   
68.
Dyspepsia is a remarkably common symptom in the general population. Although multiple definitions have been used to describe the symptom, the most common explanation is that of chronic or recurrent pain or discomfort (a subjective negative feeling that may be associated with early satiety, fullness, bloating, or nausea) centered in the upper abdomen. When a thorough evaluation of a dyspeptic patient fails to identify a cause for her symptoms, the label of nonulcer or functional dyspepsia is applied. Functional dyspepsia is a heterogeneous disorder characterized by relapsing and remitting symptoms. Treatment strategies should focus on alleviating the most bothersome symptom and can be based on the proposed underlying pathophysiology. The effect of gender on mechanisms of disease, symptom presentation, and treatment response is an area of increasing interest and study. As with other functional gastrointestinal disorders, there appear to be some gender-specific features of functional dyspepsia. Specifically, gender-related differences have been observed in some studies of both the prevalence of individual dyspepsia symptoms, and in gastric emptying and proximal gastric motor function. There also appear to be gender differences in the psychosocial realm, with dyspeptic women experiencing a lesser sense of well-being than dyspeptic men, as well as an association of an abuse history with functional dyspepsia. This review will highlight specific gender differences related to the symptom presentation, pathophysiology, and approach to treatment of functional dyspepsia, while noting where differences have not been found and where further investigation is warranted.  相似文献   
69.
Polyunsaturated fatty acids (PUFAs) are components of cell membranes and may play an immunomodulating role in the pathogenesis of atopic dermatitis (AD). The goal was to determine the impact of PUFAs on AD by dietary supplementation of infants. Based on the parents' decision on their babies' primary feeding, mothers and newborns were randomized to the supplementation with gamma-linolenic acid (GLA) or placebo for up to 6 months. Breastfed infants received GLA by supplementing their mothers. Formula diet was commercial whey hydrolysate unsupplemented with PUFAs. Of 131 eligible infants, 24 developed AD within the first year of life. Of these, nine belonged to the exclusively breastfed group (n = 58), 14 to the combined-fed group (n = 53), and one to the never breastfed group (n = 20). We could not find an influence of GLA on the development of AD. In subjects with AD, at 1 yr of age the serum-immunoglobulin E (IgE) was the lowest in the GLA-supplemented group A-subjects. In the GLA-supplemented group, GLA-levels in breast milk were similar in atopic and non-atopic infants. In the non-supplemented group the GLA-content of breast milk was 0.07% of total fatty acids in atopic infants vs. 0.17% in non-atopic infants (p < 0.01). Dietary GLA-supplementation could not prevent AD. Interestingly, the number of infants developing AD was the lowest in never breastfed children. In infants suffering from AD, GLA-supplementation seemed to reduce total IgE in the first year of life.  相似文献   
70.
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