Increased RNA Synthesis in Nuclear Monolayers of WI-38 Cells Stimulated to Proliferate

Nuclear monolayers of WI-38 cells prepared by the method of Tsai and Green were used to determine RNA synthesis in isolated nuclei in situ. In nuclear monolayers, incorporation of [(3)H]UTP into RNA is dependent on the presence of the other three nucleotide triphosphate and is abolished by actinomycin D. The extent of RNA synthesis under these conditions was measured in density-inhibited WI-38 human diploid fibroblasts at various intervals after cell proliferation was stimulated by a change of medium.RNA synthesis increases 15 min after the nutritional change and reaches a peak at 18 hr, which is also the peak of DNA synthesis. Thereafter RNA synthesis declines. Essentially similar results are obtained whether the endogenous RNA polymerase or a bacterial polymerase is used. Replacement of the stimulating medium by conditioned medium stops the increase in RNA synthesis that occurs in cultures subject to continuous stimulation. Finally, RNA synthesis in nuclear monolayers, using the endogenous RNA polymerase, occurs by chain elongation only, while re-initiation occurs with the bacterial RNA polymerase.     

Comparison of direct immunofluorescence, conventional cell culture and polymerase chain reaction techniques for detecting respiratory syncytial virus in nasopharyngeal aspirates from infants

A total of 316 samples of nasopharyngeal aspirate from infants up to two years of age with acute respiratory-tract illnesses were processed for detection of respiratory syncytial virus (RSV) using three different techniques: viral isolation, direct immunofluorescence, and PCR. Of the samples, 36 (11.4%) were positive for RSV, considering the three techniques. PCR was the most sensitive technique, providing positive findings in 35/316 (11.1%) of the samples, followed by direct immunofluorescence (25/316, 7.9%) and viral isolation (20/315, 6.3%) (p < 0.001). A sample was positive by immunofluorescence and negative by PCR, and 11 (31.4%) were positive only by RT-PCR. We conclude that RT-PCR is more sensitive than IF and viral isolation to detect RSV in nasopharyngeal aspirate specimens in newborn and infants.     

Galectina-3 Associada a Formas Graves e Mortalidade em Longo Prazo em Pacientes com Doença de Chagas

Background The histopathological characteristics of Chagas disease (ChD) are: presence of myocarditis, destruction of heart fibers, and myocardial fibrosis. Galectin-3 (Gal-3) is a biomarker involved in the mechanism of fibrosis and inflammation that may be useful for risk stratification of individuals with ChD.Objectives We sought to evaluate whether high Gal-3 levels are associated with severe forms of Chagas cardiomyopathy (CC) and whether they are predictive of mortality.Methods We studied anti-T. cruzi positive blood donors (BD): Non-CC-BD (187 BD without CC with normal electrocardiogram [ECG] and left ventricular ejection fraction [LVEF]); CC-Non-Dys-BD (46 BD with CC with abnormal ECG but normal LVEF); and 153 matched serum-negative controls. This cohort was composed of 97 patients with severe CC (CC-Dys). We used Kruskall-Wallis and Spearman’s correlation to test hypothesis of associations, assuming a two-tailed p<0.05 as significant.Results The Gal-3 level was 12.3 ng/mL for Non-CC-BD, 12.0 ng/mL for CC-Non-Dys-BD, 13.8 ng/mL for controls, and 15.4 ng/mL for CC-Dys. LVEF<50 was associated with higher Gal-3 levels (p=0.0001). In our linear regression adjusted model, we found association between Gal-3 levels and echocardiogram parameters in T. cruzi-seropositive subjects. In CC-Dys patients, we found a significant association of higher Gal-3 levels (≥15.3 ng/mL) and subsequent death or heart transplantation in a 5-year follow-up (Hazard ratio – HR 3.11; 95%CI 1.21–8.04; p=0.019).Conclusions In ChD patients, higher Gal-3 levels were significantly associated with severe forms of the disease and more long-term mortality, which means it may be a useful means to identify high-risk patients. (Arq Bras Cardiol. 2021; 116(2):248-256)     

Efficacy and safety of low intensity vitamin K antagonists in Western and East-Asian patients with left-sided mechanical heart valves

Journal of Thrombosis and Thrombolysis - The optimal INR target in patients with mechanical heart valves is unclear. Higher INR targets are often used in Western compared with East Asian countries....     

Atrial Fibrillation: The Role of Atrial Defibrillation

Dual defibrillator implantation represents an emerging option to treat patients with drug refractory atrial fibrillation. Atrial antitachycardia pacing and cardioversion have been demonstrated to be highly effective in treating spontaneous tachyarrhythmias and may reduce atrial fibrillation burden by preventing atrial remodeling. Device implantation has been associated to improved quality of life and reduced hospitalization rate. Patient selection and tailored device programming are critical as regard to clinical outcome. Individual psychological profile analysis as well as underlying heart disease and atrial fibrillation clinical patterns represent the main drivers for the right strategy. Controlled studies are needed in order to define the subset of patients who can benefit more from device implantation.     

S-phase-specific regulation by deletion mutants of the human thymidine kinase promoter.

The levels of thymidine kinase (TK; EC 2.7.1.21) mRNA were determined in nine established cell lines derived from TK-ts13, a temperature-sensitive mutant cell line that arrests in late G1 phase of the cell cycle at the restrictive temperature. The derivative cell lines carried either a cDNA or a minigene of human TK under the control of TK promoters of different lengths. A tenth cell line carried a human TK cDNA under the control of a simian virus 40 promoter. Two different assays were used to determine the S-phase-specific regulation of human TK mRNA levels in quiescent cells stimulated to proliferate. Results from these two assays indicated that (i) the first two introns of the human TK gene had no effect on the S-phase-specific regulation of TK mRNA levels, although the presence of introns increased the amount of TK mRNA; (ii) similar amounts of TK mRNA were present in cells containing constructs with an 83-base-pair (bp) promoter as with other TK promoters comprising up to approximately 4000 bp of 5' flanking sequence; (iii) a 456-bp promoter was fully S-phase-regulated, whereas the 83-bp promoter was only partially regulated; (iv) a 63-bp promoter was much less regulated than an 83-bp promoter; and (v) the crucial element in the 20-bp fragment comprising bp -83 to -64 has been localized, by site-directed mutagenesis, to the CCAAT element at -70.     

Weekly docetaxel versus CMF as adjuvant chemotherapy for elderly breast cancer patients: safety data from the multicentre phase 3 randomised ELDA trial

Within an ongoing multicentre phase 3 randomised trial (ELDA, cancertrials.gov ID: NCT00331097), early breast cancer patients, 65-79 years old, with average to high risk of recurrence, are randomly assigned to receive CMF (cyclophosphamide 600 mg/m2, methotrexate 40 mg/m2, fluorouracil 600 mg/m2, days 1-8) or docetaxel (35 mg/m2 days 1-8-15), every 4 weeks. Here we report an unplanned safety analysis prompted by an amendment introducing creatinine clearance as a tool to adjust methotrexate dose. Before such change, 101 patients with a median age of 70 were randomly assigned CMF (53 patients) or docetaxel (48 patients). At least one grades 3-4 toxic event of any type was reported in 40 (75.5%) and 19 (39.6%) patients with CMF and docetaxel, respectively (p=0.0002). Grades 3-4 hematological events were observed in 37 (69.8%) vs. 4 (8.3%) cases (p<0.0001) and grades 3-4 non-hematological toxicity in 12 (22.6%) vs. 15 (31.2%) patients (p=0.11), with CMF and docetaxel, respectively. A higher incidence of anemia, neutropenia, thrombocytopenia and febrile neutropenia was reported with CMF. Constipation, mucositis, nausea and vomiting were more common with CMF; diarrhoea, abdominal pain, dysgeusia, neuropathy and liver toxicity were more frequent with docetaxel. No significant interaction was found between the occurrence of severe toxicity and baseline variables, including creatinine clearance and geriatric activity scales. In conclusion, weekly docetaxel appears to be less toxic than CMF in terms of hematological toxicity.