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The frequency of metaphases without a Philadelphia chromosome was determined in mitogen-stimulated cultures of peripheral blood mononuclear cells (PBMC) and purified T lymphocytes (93% CD2-positive) from a patient with chronic myelogenous leukemia (CML) for 28 years. The PBMC cultures contained few Ph-negative cells (8%), but they constituted 92% of the metaphases in T cell cultures, indicating few if any Ph-positive T cells in the patient's circulation. The results demonstrate that T cells derived from the leukemic clone may fail to replace the non-neoplastic population even when CML arises in childhood and the patient survives for many years. This raises questions concerning the normal role of the bone marrow as a source of T cells after infancy, and also whether Ph-positive lymphocytes may be at a disadvantage for growth.  相似文献   
84.
This literature review emphasizes the importance of teacher training, teaching strategies, parental involvement, curricular concerns, administrative support, and social/cultural factors on the impact of nutrition education programs at the elementary school level. The characteristics, implementation, and effectiveness of selected elementary nutrition education programs are reviewed, and instructional methods and materials shown effective through research are identified and discussed.  相似文献   
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86.
All cancer chemotherapeutic agents, except altretamine, the nitrosoureas, and dactinomycin, have produced at least an isolated instance of a HSR. Certain drugs, such as L-asparaginase and mitomycin (administered intravesically), cause HSRs of significant degree in approximately 10% of patients. All four types of HSRs are represented in the reactions produced by antitumor drugs, although Type I is the most common. Some of the Type I reactions are IgE-mediated, and others are probably mediated by nonspecific release of vasoactive substances from targets such as mast cells. It is possible to continue therapy with some drugs, despite a prior HSR, if the prophylactic measures outlined in Table 2 are taken. An example of this is provided by taxol in which the lengthening of the infusion time and the administration of preventive medication allowed some patients to continue taxol therapy. The mechanisms of the HSRs have been carefully assessed in only a minority of patients who sustained such toxicity. Such evaluation would increase our understanding of this form of drug toxicity and perhaps lead to means of effectively reducing the risk and severity.  相似文献   
87.
The mechanism responsible for the decreased red blood cell (RBC) lifespan associated with feeding propylene glycol (PG)-containing diets was investigated to understand better how Heinz body-contained RBC are destroyed. Three cats were fed a diet containing 12% PG for 14 days and three other cats served as control. The experimental group developed reticulocytosis and increased Heinz body numbers. Red blood cell membrane immunoglobulih G (IgG) concentration and phagocytosis of RBC by peritoneal macrophages were lower in the PG group compared to the control group suggesting that neither IgG nor non-IgG-mediated phagocytosis was responsible for the RBC destruction. Osmotic fragility, rate of RBC proteolysis and mild mechanical fragility test results were not statistically different from controls. However, when RBC from cats fed PG were exposed to severe mechanical stress, their fragility were increased 2.2–2.8 times. Additionally, haptoglobin concentrations were decreased in the PG group. These data suggest that intravascular lysis may be involved in the pathogenesis of PG-induced RBC destruction.  相似文献   
88.
Given that abnormal visual experience during post natal development interferes with emmetropization, we proposed that eyes with hypoplastic optic nerves were predisposed to the development of refractive errors. Six of 14 patients with unilateral optic nerve hypoplasia and 5 of 22 patients with bilateral involvement had at least 4 D of myopia. Nine of the 11 patients with asymmetric bilateral involvement had relative myopia in the eye with the more abnormal optic nerve; none of the patients with symmetric bilateral involvement had a significant interocular refractive difference. Analysis of axial length measurements obtained in 10 of the 11 patients with high myopia showed a significant increase in total axial length. The presumed normal eye of patients with unilateral involvement was significantly smaller than the mean value for age-adjusted normals. We suspect that visual input to the central nervous system is one of the feedback signals involved in the regulation of ocular growth.Presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology, Sarasota, Florida, May 4, 1990Correspondence to: A.H. Weiss  相似文献   
89.
The relation between survival and tumor cell type in renal cell carcinomas was reviewed in 79 cases. The mean follow-up period was 10 years. Tumors were classified into 5 groups according to the percentage of granular cells: group 1, 0-5%; group 2, 6-20%; group 3, 21-40%; group 4, 41-80%, and group 5, over 80%. Half of the patients (50.6%) revealed less than 5% of granular cells, and almost two thirds of the patients (64.64%) had less than 20% of granular cells. Our results showed a lack of correlation between the percentage of granular cell in the tumor and long-term survival (chi 2 p > 0.9 after 10 years). When the data were analyzed in groups of patients with the same clinical stage or nuclear grading, no significant correlation between the percentage of granular cells and long-term survival was found. However, the short-term survival, up to 3 years after diagnosis, was significantly higher for patients with tumors containing less than 20% of granular cells (64.6% in comparison to 46.4% survival for patients with over 20% granular cells; chi 2 p = 0.1). In addition, our data showed a significant correlation between the survival of patients and nuclear grading (chi 2 p < 0.003) as well as the surgical staging of the tumor (chi 2 p < 0.001).  相似文献   
90.
An algorithm is described to discriminate automatically between saccades and slow eye movements. Sampled data of the eye position have been used to calculate the momentary acceleration of the eye. The higher acceleration values of the saccadic eye movements as opposed to the slow compensatory or pursuit eye movements served to differentiate between the two. The method is demonstrated by search-coil data in squirrel monkeys.  相似文献   
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