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31.
32.
Structural abnormalities of the X chromosome are rarely found in neoplastic disorders. We describe three patients with a history of idiopathic acquired sideroblastic anemia (IASA); each one had an abnormal clone of cells in the bone marrow, characterized by a structurally abnormal X chromosome. In two of these patients, the predominant karyotype was 47,X,2idic(X)(q13); in the other patient, it was 46,X,t(X;11)(q13;p15). Inasmuch as all three of these cases involved chromosome band Xq13, as did two previously published cases, we suggest that band Xq13 may be more prone to structural rearrangement than other X chromosome bands in hematologic disorders. The common Xq13 chromosome breakpoint and clinical presentation (IASA) among these three patients and the occurrence of an X-linked type of sideroblastic anemia may suggest that an association exists between X chromosome abnormalities and IASA. Perhaps alteration of a gene or chromosome structure in or near band Xq13 predisposes to development of IASA. The fact that two of these patients had preleukemia and the third had overt acute leukemia may imply that patients with IASA and X chromosome abnormalities have a poor prognosis. Cases of IASA without associated X chromosome abnormalities are known; thus, if an association between IASA and an abnormal X chromosome does exist, most likely it involves only some patients with IASA. 相似文献
33.
Plasticity of representational maps in adult cerebral cortex has been
documented in both sensory and motor cortex, but the anatomical basis for
cortical plasticity remains poorly understood. To investigate horizontal
connectivity in primary motor cortex (M1) as a putative anatomical
substrate for short-term, functional plasticity of adult motor cortical
representations, a combination of electrical stimulation and biocytin
labeling was used to examine pre-existing patterns of intrinsic connections
in adult rat M1 in relationship to the pattern of reorganization of the
motor movement may induced by transection of the contralateral facial
nerve. Two hours after nerve cut, small, circumscribed regions of the
forelimb representation expanded medially into territory previously devoted
to the vibrissae representation. Outside of this novel, expanded forelimb
region, no forelimb movement could be evoked from the former vibrissae
representation at any time over the period of hours tested, thus
representing silent cortex. Injections placed into vibrissae cortex
representing the newly expanded forelimb representation gave rise to
labeled axons and dense terminal fiber labeling which crossed the
forelimb/vibrissae border and extended up to 1.2 mm within the
low-threshold forelimb representation. In contrast, injections placed into
silent vibrissae cortex gave rise to labeled axons and terminal boutons
which remained mostly restricted to the original vibrissae representation,
with only sparse projections that crossed into the low-threshold forelimb
representation. Thus, these results suggest that the extent of short-term,
functional reorganization of M1 induced within the first several hours
following peripheral nerve cut is mediated, and constrained, by an
anatomical framework of pre-existing, horizontal projections which traverse
representation borders.
相似文献
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One hundred fifty-one consecutive patients scheduled for double-contrast barium enema studies were assigned randomly to insufflation with either air or carbon dioxide (CO2) in a double-blind, prospective trial. Within 24 hours after the enema study, the patients were contacted by telephone by an interviewer, who completed a standard questionnaire. Radiographs from the enema studies were assessed for quality by two radiologists. Pain experienced after the procedure was graded from 0 (none) to 4 (severe). Clinically relevant (grades 2-4) pain was experienced by 30% of patients after insufflation with room air, compared with 11% of patients in whom CO2 was used for insufflation (P = .005). The mean pain score for CO2 was 0.4, and for room air, 1.2 (P less than .005). Although five patients experienced grade 4 pain after insufflation with air, no patient reported severe pain after CO2 insufflation. Post-evacuation films confirmed there was significantly less residual gas in the CO2 group. The quality of radiographs was equal in the two groups. CO2 has advantages for use in the double-contrast barium enema examination. 相似文献
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Groenewegen PP Kerssens JJ Sixma HJ van der Eijk I Boerma WG 《BMC health services research》2005,5(1):16