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61.
Cytogenetic and molecular delineation of a region of chromosome 7 commonly deleted in malignant myeloid diseases 总被引:8,自引:2,他引:8
Loss of a whole chromosome 7 or a deletion of the long arm, del(7q), are recurring abnormalities in malignant myeloid diseases. To determine the location of genes on 7q that are likely to play a role in leukemogenesis, we examined the deleted chromosome 7 homologs in a series of 81 patients with therapy-related or de novo myelodysplastic syndrome or acute myeloid leukemia. Our analysis showed that the deletions were interstitial and that there were two distinct deleted segments of 7q. The majority of patients (65 of 81 [80%]) had proximal breakpoints in bands q11-22 and distal breakpoints in q31-36; the smallest overlapping deleted segment was within q22. The remaining 16 patients had deletions involving the distal q arm with a commonly deleted segment of q32-33. To define the proximal deleted segment at 7q22 at a molecular level, we used fluorescence in situ hybridization with a panel of mapped yeast artificial chromosome (YAC) clones from 7q to examine 15 patients with deletion breakpoints in 7q22. We determined that the smallest overlapping deleted segment is contained in a well- defined YAC contig that spans 2 to 3 Mb. These studies delineate the region of 7q that must be searched to isolate a putative myeloid leukemia suppressor gene, and provide the necessary cloned DNA for more detailed physical mapping and gene isolation. 相似文献
62.
A neural model of binocular integration and rivalry based on the coordination of action-potential timing in primary visual cortex 总被引:1,自引:0,他引:1
In normal vision, the inputs from the two eyes are integrated into a single
percept. When dissimilar images are presented to the two eyes, however,
they compete for perceptual dominance, so that one eye's view suppresses
that of the other. Recent evidence suggests that this phenomenon, known as
binocular rivalry, arises through competition between alternative stimulus
interpretations in extrastriate cortex. Because eye-specific information
appears to be lost at this stage, it remains unclear how the stimulus
conditions that yield binocular rivalry are distinguished from those that
produce stable single vision. Using a neural network that models the
mammalian early visual system, I investigate here the hypothesis that
congruent and conflicting stimuli are distinguished by their different
effects on the relative timing of action potentials in primary visual
cortex (V1), where monocular inputs are first combined. In the model,
congruent stimulation of both eyes results in synchronization of discharges
among binocular neurons in V1. By contrast, conflicting stimulation of the
two eyes results in neuronal asynchrony in this area. This asynchrony then
produces rivalrous response suppression at later stages in the visual
pathway. Synchronization of firing in V1, however, prevents such
competition, thereby ensuring non-rivalrous responses. These novel effects
of spike timing on competition emerge naturally from the network dynamics.
The results suggest that input-related differences in relative spike timing
at an early stage of visual processing may play an important part in the
phenomena both of binocular integration and rivalry; furthermore, they
indicate that the temporal patterning of cortical activity may be a
fundamental mechanism of selection among competing stimulus
representations.
相似文献
63.
C. McLAUGHLIN BSC Psychol RMN RGN RCNT CERT ED RNT D. WHITTINGTON MA MED Tcert AFBPS C Psychol 《Journal of psychiatric and mental health nursing》1996,3(1):13-20
This study compares government records of death by suicide, in Northern Ireland, during two quinquennia in the decade 1982–1991. Specifically these quinquennia are 1982–1986 l 1987–1991. During the latter quinquennium there was an increse m rate for males in most age groups, except the 45–54 and the over 65 years age groups. However, females had an increased rate in the 15–24 and 35–54 years age groups, but have a decreased rate in the other age groups. There has been a decrease in the rate of suicides by poisoning with solids and liquids for both sexes. However, male suicide rates by more violent methods have increased substantially during the latter quinquennium. Three cohorts of males, those in the 15–24, 25–34, and 55–64 age groups, have shown substantial increases during the latter quinquennium. Suggestions for psychiatric intervention strategies are made. 相似文献
64.
65.
All managerial deciions are taken on the basis of the information. It is important that managers use appropriate information to base their decisions upon about service provision to ensure erhcient use or resources. This basic premise serves as a framework for examining how quantitative and qualitative information can be of help to nurse managers in taking these decisions in the context of developing services for informal carers. The current emphasis on surveys as a means of assessing client need is questioned, and it is suggested that a wealth of evidence, relating to the experience of carers, already exists. Examples of accounts which express the needs of informal carers are presented and their utility, in terms of highlighting the carers' perspective, is discussed to reinforce the importance of utilizing this information. The paper concludes that nurse managers can use these sources as a basis for decision-making in the area of service provision and this may result in a more effective use of resources through a needs-based approach. 相似文献
66.
J. LLOYD RGN ONC RCNT RNT CERT ED 《Journal of nursing management》1994,2(3):121-128
This paper describes the development over a 3-year-period of short management courses for registered nurses offered as part of a professional development educational programme by Oxfordshire Health Authority (OHA) Clinical Education and Practice Team (OXCEPT). The courses were seen as role development for staff nurses, team leaders, sisters, charge nurses and senior sisters, and the content and length of courses were altered, extended and developed in response to evaluation of the courses by tutors and participants. The emphasis is on integrating participants' clinical, managerial and educational roles, as professional practitioners managing nurses and nursing. 相似文献
67.
68.
ED Williams 《Journal of clinical pathology》1984,37(1):105-106
69.
70.
Inflammatory carcinoma of the breast 总被引:2,自引:0,他引:2