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41.
The main aim of the present experiment was to determine whether extensive musical training facilitates pitch contour processing not only in music but also in language. We used a parametric manipulation of final notes' or words' fundamental frequency (F0), and we recorded behavioral and electrophysiological data to examine the precise time course of pitch processing. We compared professional musicians and nonmusicians. Results revealed that within both domains, musicians detected weak F0 manipulations better than nonmusicians. Moreover, F0 manipulations within both music and language elicited similar variations in brain electrical potentials, with overall shorter onset latency for musicians than for nonmusicians. Finally, the scalp distribution of an early negativity in the linguistic task varied with musical expertise, being largest over temporal sites bilaterally for musicians and largest centrally and over left temporal sites for nonmusicians. These results are taken as evidence that extensive musical training influences the perception of pitch contour in spoken language.  相似文献   
42.
Using a culture system that includes a B-enriched fraction of peripheral blood lymphocytes (PBL) mixed with non-proliferating "filler" cells (mitomycin-treated PBL or T cells), the kinetics of human B cell proliferation and differentiation into cells containing cytoplasmic immunoglobulin (cIg) have studied. Following stimulation with phytohaemagglutinin (PHA) or pokeweed mitogen (PWM), proliferative responses of enriched B cells were comparable to those for unseparated PBL, with a peak at 3 to 5 days and a steep decline thereafter; cIg-positive cells increased with both mitogens from day 3 until 7. Little proliferation or differentiation occurred in B cell cultures lacking T "filler" cells. The results indicate that human B cells can respond polyclonally to PHA in vitro, as well as to PWM, if non-proliferating T cell "help" is present. Further, these proliferative responses, but not subsequent differentiation, were inhibited by PHA-stimulated blasts that were treated with mitomycin and added on day 3 of culture.  相似文献   
43.
Recent advances in automatic speech recognition and related technologies allow computers to carry on conversations by telephone. We developed an intelligent dialogue system that interacts with hypertensive patients to collect data about their health status. Patients thus avoid the inconvenience of traveling for frequent face to face visits to monitor the clinical variables they can easily measure at home; the physician is facilitated in acquiring patient information and cardiovascular risk, which is evaluated from the data according to noted guidelines. Controlled trials to assess the clinical efficacy are under way.  相似文献   
44.
45.
Inactivation of mismatch repair (MMR) genes has been linked to the hereditary nonpolyposis colon cancer syndrome and to a subset of sporadic cancers. A phenotypic characteristic of tumors with defective MMR is microsatellite instability (MSI). Although MSI has been reported in a proportion of cutaneous melanomas, inactivation of MMR genes in this tumor type has not been detected thus far. We recently described a human melanoma cell line, PR-Mel, and a cutaneous metastasis from the same patient, which displayed a MMR defect, and showed high MSI. Here we report that in the PR-Mel cell line both MLH1 alleles are somatically inactivated. One allele is lost through a chromosomal deletion of the region 3p21-24, whereas the remaining allele harbors a G --> A transition at position -1 of the acceptor splice site of intron 15, leading to the in-frame skipping of exon 16. The primary melanoma of the PR patient shows loss of heterozygosity at the BAT21 microsatellite marker, located in the MLH1 gene, and does not express the MLH1 and PMS2 proteins. Moreover, it harbors the same mutation detected in the PR-Mel cells. These results demonstrate that biallelic inactivation of MLH1 had occurred in the primary melanoma of the PR patient and suggest that disruption of MMR might have had a role in the development of the melanoma. This is the first report in which genetic defects leading to disruption of MMR function in a human melanoma have been identified.  相似文献   
46.
Birds belonging to 59 species (n = 1,206) were live captured in Piemonte, northwestern Italy, in 2001. Ixodes ricinus (L.) larvae were collected from 59 birds belonging to nine species, and nymphs were recovered on 79 birds belonging to 10 species. Eurasian blackbirds, Turdus merula L., had significantly higher levels of infestation by ticks than other passerine species. Larval I. ricinus of blackbirds peaked in summer, when prevalence was 39% (95% confidence interval 24.2-55.5) and mean number of ticks per host was 3.3 (1.6-7.2), whereas nymphs peaked in spring, when prevalence was 72.2% (54.8-85.8) and mean number of ticks per host was 6.9 (4.4-10.7). Immature I. ricinus were coincidentally aggregated on blackbirds, with 15 blackbirds feeding 67.4% of nymphs and 40.3% of larvae, and coinfestation by both stages was relatively high in summer: Kappa = 0.64 (0.40-0.88). Borrelia burgdorferi sensu lato was identified by polymerase chain reaction (PCR) in 58.3% (35.9-78.5) of larvae with engorgement ratio > or = 3 that were collected from blackbirds. Larvae that were collected from other passerine species gave negative PCR results. Sixteen of 21 PCR-positive samples belonged to B. garinii (76.2%), and five (23.8%) were Borrelia valaisiana. Results of this study suggest that blackbirds play an important role as hosts for immature I. ricinus and as reservoir of Borrelia garinii in northwestern Italy.  相似文献   
47.
Transplantation Centers using human cytomegalovirus (HCMV) antigenemia-based preemptive therapy will need to replace in the near future the antigenemia assay with a more standardized and automatable assay, such as a molecular assay quantifying HCMV DNA in blood (DNAemia). Thus, in view of replacing antigenemia with clinically safe cutoff values, DNAemia levels corresponding to antigenemia cutoffs guiding HCMV preemptive therapy were determined retrospectively in solid organ and hematopoietic stem cell transplant recipients (HSCTR) using an "in-house" quantitative PCR (QPCR) method. Since preemptive therapy had prevented appearance of HCMV disease in all patients tested, DNA cutoffs determined retrospectively had to be considered as safe clinically as antigenemia cutoffs used prospectively. However, in solid organ transplant recipients (SOTR), initiating preemptive therapy upon an antigenemia cutoff of 100 pp65-positive leukocytes, a DNAemia cutoff of 300,000 copies/ml blood had positive and negative predictive values of >90%, indicating that a DNAemia cutoff could achieve, in terms of prevention of HCMV disease, the same clinical results as the antigenemia cutoff. In HSCTR, initiating preemptive therapy upon first antigenemia positivity, a DNAemia cutoff of 10,000 copies/ml blood had a positive predictive value of >90%, indicating that the great majority of patients treated under the antigenemia guidance would have been treated also using this DNA cutoff. On the other hand, the negative predictive value of 28.6% indicated that two out of three HSCTR had been treated under the antigenemia guidance having the same levels of viral DNA as the untreated patients. The data suggest that a quantitative cutoff could be adopted as a guiding criterion for preemptive therapy also in HSCTR. Regression analysis allowed to determine the DNAemia (corresponding to QPCR) cutoff values for two commercial assays tested both in solid organ and HSCTR. Retrospective DNAemia cutoff values will be verified for safety in prospective trials.  相似文献   
48.
Distinction between recurrent and de novo hepatocellular carcinoma (HCC) after orthotopic liver transplantation (OLT) bears important clinical and therapeutic implications. Techniques for molecular profiling of clinically suspected de novo and recurrent HCC are required since the histological/clinical discrimination of donor vs. recipient tumor origin is difficult. Multiple PCR amplification of 16 highly polymorphic short tandem repeat (STR) DNA sequences (routinely used for paternity and forensic assays) was applied in two patients who developed a second HCC after OLT. In both patients the technique provided reliable evidence that the two second HCC were recurrences of the primary tumor. Multiple STR genetic allelotyping is an effective tool for clear-cut discrimination of donor/recipient origin of a second HCC after OLT. Its application could be of great therapeutic relevance for such OLT patients.  相似文献   
49.
Postnatal development in the expression of dopamine D1-like and D2-like receptors was investigated in peripheral blood lymphocytes of male Wistar rats aged 1, 3, 4, 8, 12 and 16 weeks of age by radioligand binding assay techniques. Sample of frontal cortex, striatum and hippocampus were also investigated as reference tissues. The dopamine D1-like receptor antagonist [3H]SCH 23390 and the dopamine D2-like receptor agonist [3H]7-OH-DPAT were used as radioligands. The affinity (K(d)) of [3H]SCH 23390 or of [3H]7-OH-DPAT binding was unchanged in lymphocytes of rats of different age groups. The density (B(max)) of [3H]SCH 23390 binding sites increased from the 1st to the 3rd week of age, remained constant from the 3rd to the 8th week of age, and then increased slightly at 12 and 16 weeks of age. The B(max) value of [3H]7-OH-DPAT binding to lymphocytes increased from the 1st to the 3rd week of age, remained constant from the 3rd to the 4th week, increased again until the 12th week and then plateaued. Dopamine D1-like and D2-like receptor maturation in frontal cortex, hippocampus and striatum revealed an increased receptor density until the 4th week of age and a relative stabilization of receptor density values between the 4th to the 12th week depending on the area considered. Comparatively postnatal maturation of lymphocyte dopamine D1-like receptors displayed a pattern different from that of brain areas investigated, whereas maturation of D2-like receptors displayed a pattern similar to that of striatum. The quantitative and/or qualitative dissimilarities between development of lymphocyte and brain dopamine receptors suggest that from a developmental point of view lymphocyte dopamine receptors probably cannot be considered as a marker of homologous brain receptors.  相似文献   
50.
Summary The yeast Saccharomyces cerevisiae has been engineered to synthesize and secrete desulfato-hirudin (hirudin), a thrombin inhibitor from the leech Hirudo medicinalis. The synthetic gene coding for hirudin was expressed constitutively under the control of four size-variants of the yeast glyceraldehyde-3-phosphate dehydrogenase promoter (GAP) and cloned into a 2 based multicopy yeast vector. The constitutive action of the four promoter variants was confirmed by demonstrating that the expression and secretion of hirudin is growth-related. The different efficiencies of the promoter variants not only affected hirudin expression but also led to changes in several cellular parameters, such as cell growth, average plasmid copy number and plasmid stability. The observed changes show that yeast cells establish a specific equilibrium for each promoter variant. We conclude, that the adjustment of cellular parameters in response to the expression levels of a heterologous protein is regulated by two counteracting selective forces: (1) the need for complementation of the auxotrophic host marker by the plasmid-encoded selection gene which, in the case of dLEU2, requires several plasmid copies; and (2) a selective advantage of cells with a lower copy number enabling them to escape the burden of heterologous protein production.  相似文献   
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