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41.
Characterization of a Salmonella typhimurium hisU mutant defective in tRNA precursor processing. 总被引:3,自引:0,他引:3
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The DA11 mutant of Salmonella typhimurium, originally isolated as derepressed for the histidine operon, carries a temperature-dependent alteration in a nucleolytic enzyme specifically involved in the maturation of tRNA. As a consequence of this alteration, no detectable synthesis of any mature tRNA species occurs in DA11 upon shift at 43 degrees C, whereas many tRNA precursors, whose sizes range between 80 and 750 nucleotides, do accumulate. Kinetic studies on the synthesis and processing of these maturation intermediates show that these molecules represent different stages in the maturation pathway, most of them being the products of previous nucleolytic events. These RNA molecules are in vivo substrates of methylation and thiolation enzymes and can be cleaved in vitro to 4S RNA by wild-type but not by DA11 cell-free extract. Evidence is presented that DA11 is very probably a ribonuclease P mutant. 相似文献
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R De Mercato R Ciampi D Guarnaccia M Esposito P Ragone U Celentano G Iannoni V Iovinella J P Cantiello C Romano 《Bollettino della Società italiana di biologia sperimentale》1990,66(10):977-984
Using the antibody to HCV and HBc (anti-HCV, anti-HBc), we studied the prevalence of Hepatitis C and B virus in three groups: intravenous drug abusers, subjects lodging in huts and elderly clergymen. Statistical analysis was carried out by chi-square and Fisher's exact tests. Our results show statistical significance for anti-HCV seroprevalence among the three groups, while anti-HBc doesn't differ. These preliminary data seem to show that the two viruses have different ways of transmission. 相似文献
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Pseudouridylate synthetase from Salmonella typhimurium has been purified 1,000 fold and is about 90% pure. The enzyme has a molecular weight of 50,000 daltons. In the presence of tRNA there is a change in molecular weight from 50.000 to 100.000. This change does not seem to be due to the formation of a tRNA-enzyme complex but rather to a tRNA induced dimerization. Other properties of the enzyme are described. 相似文献
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Carlos Zamudio Fiorella Krapp Howard W. Choi Lena Shah Antonio Ciampi Eduardo Gotuzzo Jody Heymann Carlos Seas Timothy F. Brewer 《PloS one》2015,10(2)
BackgroundTuberculosis (TB) transmission may occur with exposure to an infectious contact often in the setting of household environments, but extra-domiciliary transmission also may happen. We evaluated if using buses and/or minibuses as public transportation was associated with acquiring TB in a high incidence urban district in Lima, Peru.MethodsNewly diagnosed TB cases with no history of previous treatment and community controls were recruited from August to December 2008 for a case-control study. Crude and adjusted odd ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression to study the association between bus/minibus use and TB risk.ResultsOne hundred forty TB cases and 80 controls were included. The overall use of buses/minibuses was 44.9%; 53.3% (72/135) among cases and 30.4% (24/79) among controls [OR: 3.50, (95% CI: 1.60–7.64)]. In the TB group, 25.7% (36/140) of subjects reported having had a recent household TB contact, and 13% (18/139) reported having had a workplace TB contact; corresponding figures for controls were 3.8% (3/80) and 4.1% (3/73), respectively[OR: 8.88 (95% CI: 2.64–29.92), and OR: 3.89 (95% CI: 1.10–13.70)]. In multivariate analyses, age, household income, household contact and using buses/minibuses to commute to work were independently associated with TB [OR for bus/minibus use: 11.8 (95% CI: 1.45–96.07)].ConclusionsBus/minibus use to commute to work is associated with TB risk in this high-incidence, urban population in Lima, Peru. Measures should be implemented to prevent TB transmission through this exposure. 相似文献
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Brewer TF Choi HW Seas C Krapp F Zamudio C Shah L Ciampi A Heymann SJ Gotuzzo E 《PloS one》2011,6(10):e25861
Background
Multiple drug-resistance in new tuberculosis (TB) cases accounts for the majority of all multiple drug-resistant TB (MDR-TB) worldwide. Effective control requires determining which new TB patients should be tested for MDR disease, yet the effectiveness of global screening recommendations of high-risk groups is unknown.Methods
Sixty MDR-TB cases with no history of previous TB treatment, 80 drug-sensitive TB and 80 community-based controls were recruited in Lima, Peru between August and December, 2008 to investigate whether recommended screening practices identify individuals presenting with MDR-TB. Odd ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression to study the association of potential risk factors with case/control variables.Results
MDR-TB cases did not differ from drug-sensitive TB and community controls in rates of human immunodeficiency virus infection, reported hospital or prison visits in the 3 years prior to diagnosis. MDR-TB cases were more likely than drug-sensitive TB controls to have had a recent MDR-TB household contact (OR 4.66, (95% CI 1.56–13.87)); however, only 15 cases (28.3%) reported this exposure. In multivariate modeling, recent TB household contact, but not contact with an MDR-TB case, remained predictive of MDR-TB, OR 7.47, (95% CI 1.91–29.3). Living with a partner rather than parents was associated with a lower risk of MDR-TB, OR 0.15, (95% CI 0.04–0.51).Conclusion
Targeted drug susceptibility testing (DST) linked to reported MDR-TB contact or other high-risk exposures does not identify the majority of new TB cases with MDR disease in Lima where it is endemic. All new TB cases should be screened with DST to identify MDR patients. These findings are likely applicable to other regions with endemic MDR-TB. 相似文献48.
Congestive heart failure with preserved left ventricular systolic function has emerged as a growing epidemic medical syndrome in developed countries, which is characterized by high morbidity and mortality rates. Rapid and accurate diagnosis of this condition is essential for optimizing the therapeutic management. The diagnosis of congestive heart failure is challenging in patients presenting without obvious left ventricular systolic dysfunction and additional diagnostic information is most commonly required in this setting. Comprehensive Doppler echocardiography is the single most useful diagnostic test recommended by the ESC and ACC/AHA guidelines for assessing left ventricular ejection fraction and cardiac abnormalities in patients with suspected congestive heart failure, and non-invasively determined basal or exercise-induced pulmonary capillary hypertension is likely to become a hallmark of congestive heart failure in symptomatic patients with preserved left ventricular systolic function. The present review will focus on the current clinical applications of spectral tissue Doppler echocardiography used as a reliable noninvasive surrogate for left ventricular diastolic pressures at rest as well as during exercise in the diagnosis of heart failure with preserved left ventricular systolic function. Chronic congestive heart failure, a disease of exercise, and acute heart failure syndromes are characterized by specific pathophysiologic and diagnostic issues, and these two clinical presentations will be discussed separately. 相似文献
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Maria Teresa De Angelis Gianluca Santamaria Elvira Immacolata Parrotta Stefania Scalise Michela Lo Conte Sara Gasparini Edoardo Ferlazzo Umberto Aguglia Clara Ciampi Antonella Sgura Giovanni Cuda 《Journal of cellular and molecular medicine》2019,23(11):7382-7394
Involvement of the central nervous system (CNS) is an uncommon feature in systemic lupus erythematosus (SLE), making diagnosis rather difficult and challenging due to the poor specificity of neuropathic symptoms and neurological symptoms. In this work, we used human‐induced pluripotent stem cells (hiPSCs) derived from CNS‐SLE patient, with the aim to dissect the molecular insights underlying the disease by gene expression analysis and modulation of implicated pathways. CNS‐SLE‐derived hiPSCs allowed us to provide evidence of Erk and Akt pathways involvement and to identify a novel cohort of potential biomarkers, namely CHCHD2, IDO1, S100A10, EPHA4 and LEFTY1, never reported so far. We further extended the study analysing a panel of oxidative stress‐related miRNAs and demonstrated, under normal or stress conditions, a strong dysregulation of several miRNAs in CNS‐SLE‐derived compared to control hiPSCs. In conclusion, we provide evidence that iPSCs reprogrammed from CNS‐SLE patient are a powerful useful tool to investigate the molecular mechanisms underlying the disease and to eventually develop innovative therapeutic approaches. 相似文献
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Margherita Maffei Marcella Funicello Teresa Vottari Olimpia Gamucci Mario Costa Simonetta Lisi Alessandro Viegi Osele Ciampi Giuseppe Bardi Paolo Vitti Aldo Pinchera Ferruccio Santini 《BMC biology》2009,7(1):1-14