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Leslie K Jacobsen Kenneth R Pugh Robert T Constable Michael Westerveld W Einar Mencl 《Neuropsychopharmacology》2007,61(1):31-40
BACKGROUND: Cannabis remains the most widely used illicit substance by adolescents and is typically consumed by this population in the context of ongoing tobacco use. Human studies have shown that both cannabis and tobacco exert effects on cognitive function; however, little is known about possible interacting effects of these drugs on brain function and cognition during adolescent development. METHODS: Verbal learning and memory were assessed in 20 adolescent users of tobacco and cannabis and 25 adolescent tobacco users with minimal history of cannabis use. Functional magnetic resonance imaging was used to examine brain function and functional connectivity while a subset of these subjects performed a verbal working memory task. RESULTS: Delayed recall of verbal stimuli deteriorated during nicotine withdrawal among cannabis users but not among comparison subjects. During high verbal working memory load, nicotine withdrawal selectively increased task-related activation of posterior cortical regions and was associated with disruption of frontoparietal connectivity in adolescent cannabis users relative to comparison subjects. CONCLUSIONS: These observations suggest that cannabis use during adolescent development may disrupt neurocircuitry supporting verbal memory formation and that deficits associated with disruption of these neurocircuits are unmasked during nicotine withdrawal. 相似文献
3.
Uroscopy in the 21st century: high-field NMR spectroscopy 总被引:1,自引:1,他引:0
Neild GH; Foxall PJ; Lindon JC; Holmes EC; Nicholson JK 《Nephrology, dialysis, transplantation》1997,12(3):404-417
From the experiments described, it can be seen that there are different
research approaches that can be taken and these are summarized in Table 1.
Whereas much scientific research is principally hypothesis led, there
remains, nevertheless, an important place for exploratory research. High
resolution NMR can measure, directly and simultaneously, a wide range of
endogenous metabolites in biological fluids and has the unique capability
of providing structural information on the metabolites detected. It has
proved to be a powerful research tool with which to study inherited
metabolic diseases, renal disease, drug metabolism, and toxicity, and can
be used to monitor the effects of drug therapy. For instance, by using a
library of experimental toxins one can map the metabolic profile of
site-specific nephron injury. With this approach in man one could
eventually take an unknown disease such as Balkan nephropathy and predict
the initial site of tubular injury, the mode of injury and therefore the
kind of toxin capable of producing that injury. NMR spectroscopic
techniques are still advancing rapidly, with ever increasing sensitivity
and sophistication of NMR pulse sequences to enhance structural elucidation
in complex mixtures. Given the advances in directly coupled HPLC-NMR and
even HPLC-NMR-mass spectroscopy it is likely that these technologies in
conjunction with pattern recognition will make major contribution to our
understanding of renal processes and provide new diagnostic insights in the
21st century.
相似文献
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Background
Correct diagnosis in psychiatry may be improved by novel diagnostic procedures. Computerized Decision Support Systems (CDSS) are suggested to be able to improve diagnostic procedures, but some studies indicate possible problems. Therefore, it could be important to investigate CDSS systems with regard to their feasibility to improve diagnostic procedures as well as to save time. 相似文献6.
G. Pals A. W. Eriksson J. C. Pronk R. R. Frants E. C. Klinkenberg-Knol A. Bosma B. D. Westerveld R. T. Taggart I. M. Samloff S. G. M. Meuwissen 《Clinical genetics》1988,34(2):90-97
The pepsinogen A (PGA) isozymogens in the gastric mucosa and Barrett epithelium of a female patient with Barrett esophagus were studied on different occasions during a 3-year period by electrophoretic analysis of in vivo steady-state pepsinogen in biopsies by activity staining in combination with variant specific monoclonal antibodies and of de novo synthesized pepsinogen by autoradiography. In Barrett epithelium only one (Pg3) or two (Pg3 and Pg5) primary PGA gene products were detected, whereas in gastric mucosal biopsies three (Pg3, Pg4 and Pg5) primary gene products were demonstrated on all occasions. These differences strongly suggest differential expression/activation of individual gene numbers in the PGA gene cluster in Barrett esophagus and are in line with the preneoplastic nature of this condition. The mechanism behind this deregulation is currently under investigation by cell biology and molecular genetic techniques. 相似文献
7.
A specific subset of solid childhood tumors-Wilms' tumor, adrenocortical carcinoma, rhabdomyosarcoma, and hepatoblastoma-is characterized by its association with Beckwith-Wiedemann syndrome. Genetic abnormalities found in these tumors affect the same chromosome region (11p15), which has been implicated in the etiology of Beckwith-Wiedemann syndrome. This suggests that the development of these tumors occurs along a common genetic pathway involving chromosome 11. To search for additional common genetic pathways, this article reviews the genetic data published for these tumors. It was found that, up until now, the only genetic abnormalities detected in all four tumors affect chromosome band 11p15 and the TP53 gene. In addition, there are several aberrations that occur in two or three of the neoplasms. It is concluded that, of the four tumors, the genetic relationship is most evident between Wilms' tumor and rhabdomyosarcoma. 相似文献
8.
A Meager H E Graves J R Walker D C Burke D M Swallow A Westerveld 《The Journal of general virology》1979,45(2):309-321
Forty-two primary human-mouse cell hybrids, derived in two separate experiments, were treated with Newcastle disease virus (NDV): eight hybrids were found to produce human interferon and this was shown in every case to be predominantly of the fibroblast type. An extensive analysis was made in terms of karyotype and marker enzymes on all the eight hybrids producing interferon and also on five hybrids which did not produce interferon, five randomly selected hybrids and eleven subclones resistant to diphtheria toxin. The results suggest that, contrary to previous reports, a gene on chromosome 5 is not involved in production of human interferon. Its production was however correlated with the presence of chromosome 9 in the hybrids. Analyses of two sets of human-Chinese hamster hybrid subclones from two different crosses were also consistent with the assignment of a human interferon gene to chromosome 9. 相似文献
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10.
Cystic hypersecretory carcinoma (CHC) is a rare variant of intraductal carcinoma. A CHC in a 50-year-old woman was excised and processed for light and electron microscopy and immunohistochemistry. The tumor had a marked cystic appearance. The walls of the cysts consisted of epithelial and myoepithelial cells and a well-developed basement membrane. The epithelial cells contained well-developed rough-surfaced endoplasmatic reticulum and Golgi apparatus. Secretory granules were not detected, with the exception of a few mucus-producing cells. The secretion was predominantly homogenous, reminiscent of thyroid colloid, and demonstrated distinct PAS positivity. The cells displayed a strong labeling with epithelial membrane antigen (EMA) and EMA-positive structures were observed within the intraluminal secretion, too. Some of these were stained by alcian blue. In addition, the colloid-like material was admixed with mucus showing a filamentous internal structure and lipid droplets resulting in some heterogenity of the secretion. Intraductal micropapillary proliferation in some of the cysts and adjacent nondistended ducts was a further defining feature of the tumor. Steroid hormone receptor and Ki-67 proliferation marker immuno his Tochemistry showed scattered positivity among the tumor cells. These results are in agreement with previous observations and further clarify the nature of this low-grade in situ cancer. 相似文献