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171.
172.
JR Hoff 《Canadian Metallurgical Quarterly》1998,5(2):46-47
Neuroimaging techniques have a great impact on the evaluation and treatment of patients with epilepsy. Positron emission tomographic studies with 18F-FDG can provide valuable data for presurgical localization of epileptogenic zones. There are also a number of receptor ligands for PET studies available, including benzodiazepine, opiate and cholinergic tracers. Ligands for monoamine oxidase B and glutamate receptors are being developed. 相似文献
173.
SK Kumanyika JR Landis YL Matthews-Cook SL Almy SJ Boehmer 《Canadian Metallurgical Quarterly》1998,148(6):528-538
Recent blood pressure trends reflect progress in hypertension control, but prevalent drug therapy precludes direct estimation of the component due to primary prevention. In data gathered on persons aged 35-74 years in three successive US health examination surveys (1960-1980), systolic blood pressure levels assuming no drug therapy were imputed by reassigning blood pressure to the upper end of the distribution for respondents reporting use of antihypertensive medication. Blood pressure was partitioned into four ordinal categories based on weighted percentiles of the 1960-1962 distributions for 35- to 44-year-old males and females who reported no use of antihypertensive medication. Cumulative logit models (alpha = 0.01) were used to estimate age- and sex-specific trends for blacks and whites within two strata (<25 or > or =25) of body mass index (BMI) (weight (kg)/height (m)2). Before imputation, systolic blood pressure decreased between 1960 and 1980; after imputation, significant decreases remained only in 35- to 44-year-olds. Strong associations of black race and BMI > or =25 with higher blood pressures were present in models with and without drug therapy. Thus, according to the models, there has been little progress in decreasing racial or BMI-related blood pressure differentials. Above the age of 44 years, blood pressure trends were largely attributable to medication use. In contrast, data for 35- to 44-year-olds suggest progress in primary prevention. 相似文献
174.
JR Goss ME O''Malley L Zou SD Styren PM Kochanek ST DeKosky 《Canadian Metallurgical Quarterly》1998,149(2):301-309
A between-side comparison of GABAA receptor subunit expression levels in the globus pallidus and anterior-pole motor thalamic nuclei of rats with an ibotenate lesion of the striatum, and rats receiving a fetal striatal graft in the lesioned area was made by using immunocytochemistry with subunit-specific antibodies, at different times post-lesion or different times post-grafting. At 10 days post-lesion, there was already an increase in the labeling of the alpha 1- and beta 2/3-subunits in the globus pallidus, entopeduncular nucleus and ventrolateral nucleus ipsilateral to the lesion when compared with the contralateral side, while there were no significant changes at the level of the ventromedial nucleus. Labeling of the alpha 2-subunit showed a clear increase in the entopeduncular nucleus compared with the contralateral side at 10 days post-lesion. Similar changes were also observed for the different subunits studied at 30 and 120 days after lesioning. Rats with 20-day old transplants of fetal striatal neurons that were implanted in the ibotenate lesioned striatum at 10 days post-lesioning, continued to show changes in the expression of GABAA receptor subunits, albeit at a lower level than those of ibotenate lesioned rats at similar age post-lesion. However, when examining rats with 70-day old transplants, the ibotenate-lesion induced between-side changes were almost completely compensated. These findings suggest a correlation between the maturation of the grafts and their capability to function in reestablishing neuronal circuits as shown by the reduction of changes in GABAergic transmission induced by ibotenate lesions, as indicated by the reversal of changes in GABAA receptor subunit in several areas of the basal ganglia circuit. 相似文献
175.
Understanding the mechanisms responsible for photodamage to the skin is most important for dermatology. 3-D cultures have been used as tools to mimic the in vivo situation for several years. We irradiated such a system containing human dermal fibroblasts cultured in collagen gels, a well-known model considered to be a dermal equivalent, which reproduces the interaction between cells and the surrounding extracellular matrix. The effects of solar irradiation (315-800 nm) on the steady-state levels of the mRNAs of extracellular matrix components (type I and III collagens) and their degrading enzymes (interstitial collagenase, MMP-1 and stromelysin 1, MMP-3) were measured. Exposure to low levels of solar radiation (0-10 J cm-2 in the UVA, i.e. suberythemal UVA doses) caused a transient decrease in type I procollagen mRNA, an increase in MMP-mRNA, and no change in type III procollagen mRNA steady-state levels. These results describe the early changes in the connective tissue of the skin following exposure to low-level solar stimulation, and may help explain the long-term changes in photodamaged skin. 相似文献
176.
JR Eshleman PS Donover SJ Littman SE Swinler GM Li JD Lutterbaugh JK Willson P Modrich WD Sedwick SD Markowitz ML Veigl 《Canadian Metallurgical Quarterly》1998,16(9):1125-1130
We describe a novel mutator phenotype in the Vaco411 colon cancer cell line which increases the spontaneous mutation rate 10-100-fold over background. This mutator results primarily in transversion base substitutions which are found infrequently in repair competent cells. Of the four possible types of transversions, only three were principally recovered. Spontaneous mutations recovered also included transitions and large deletions, but very few frameshifts were recovered. When compared to known mismatch repair defective colon cancer mutators, the distribution of mutations in Vaco411 is significantly different. Consistent with this difference, Vaco411 extracts are proficient in assays of mismatch repair. The Vaco411 mutator appears to be novel, and is not an obvious human homologue of any of the previously characterized bacterial or yeast transversion phenotypes. Several hypotheses by which this mutator may produce transversions are presented. 相似文献
177.
EL Palacios-Prü L Miranda-Contreras RV Mendoza-Brice?o JR Lozano-Hernández 《Canadian Metallurgical Quarterly》1998,18(2):267-284
1. Information obtained during the last decade has demonstrated that hypothalamic neurons release a wide variety of neuroactive substances, such as neurotransmitters, mostly monoamines and amino acids, and neuromodulators such as the peptides vasopressin (AVP) and oxytocin (OXT) and hypophysial releasing hormones. 2. Synapse formation between hypothalamic neurons was followed at different times within a given nucleus and among different nuclei during development of the mouse hypothalamus. 3. The amounts of various neurotransmitters and hormones were determined at various stages of development. 4. A correlation is presented of the biochemical and ultrastructural features and their functional implications during maturation. 相似文献
178.
179.
A Bhandari DG Jones JR Schullek K Vo CA Schunk LL Tamanaha D Chen Z Yuan MC Needels MA Gallop 《Canadian Metallurgical Quarterly》1998,8(17):2303-2308
Phosphomannose Isomerase (PMI) has been shown by genetic methods to be an essential enzyme in fungal cell wall biosynthesis. The PMI inhibitor AF14049 was discovered as an unanticipated side product from high-throughput library screening against the enzyme from C, albicans. Solid-phase synthetic methods were developed and a series of libraries and discrete analogs synthesized to explore SAR around AF14049. 相似文献
180.
DK Ball GA Surveyor JR Diehl CL Steffen M Uzumcu MA Mirando DR Brigstock 《Canadian Metallurgical Quarterly》1998,59(4):828-835