208 research outputs found

    Investigation Of The Interactions Between Pt(II) And Pd(II) Derivatives Of 5,10,15,20-Tetrakis (N-Methyl-4-Pyridyl) Porphyrin And G-Quadruplex DNA

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    G-quadruplexes are non-canonical DNA structures formed by guanine-rich DNA sequences that are implicated in cancer and aging. Understanding how small molecule ligands interact with quadruplexes is essential both to the development of novel anticancer therapeutics and to the design of new quadruplex-selective probes needed for elucidation of quadruplex biological functions. In this work, UV–visible, fluorescence, and circular dichroism spectroscopies, fluorescence resonance energy transfer (FRET) melting assays, and resonance light scattering were used to investigate how the Pt(II) and Pd(II) derivatives of the well-studied 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) interact with quadruplexes formed by the human telomeric DNA, Tel22, and by the G-rich sequences from oncogene promoters. Our results suggest that Pt- and PdTMPyP4 interact with Tel22 via efficient π–π stacking with a binding affinity of 106–107 M−1. Under porphyrin excess, PtTMPyP4 aggregates using Tel22 as a template; the aggregates reach maximum size at [PtTMPyP4]/[Tel22] ~8 and dissolve at [PtTMPyP4]/[Tel22] ≤ 2. FRET assays reveal that both porphyrins are excellent stabilizers of human telomeric DNA, with stabilization temperature of 30.7 ± 0.6 °C for PtTMPyP4 and 30.9 ± 0.4 °C for PdTMPyP4 at [PtTMPyP4]/[Tel22] = 2 in K+ buffer, values significantly higher as compared to those for TMPyP4. The porphyrins display modest selectivity for quadruplex vs. duplex DNA, with selectivity ratios of 150 and 330 for Pt- and PdTMPyP4, respectively. This selectivity was confirmed by observed ‘light switch’ effect: fluorescence of PtTMPyP4 increases significantly in the presence of a variety of DNA secondary structures, yet the strongest effect is produced by quadruplex DNA

    Survey of Obstetrician-Gynecologists in the United States About Toxoplasmosis

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    Background: Although the incidence of toxoplasmosis is low in the United States, up to 6000 congenital cases occur annually. In September 1998, the Centers for Disease Control and Prevention held a conference about toxoplasmosis; participants recommended a survey of the toxoplasmosis-related knowledge and practices of obstetrician-gynecologists and the development of professional educational materials for them. Methods: In the fall of 1999, surveys were mailed to a 2% random sample of American College of Obstetricians and Gynecologists (ACOG) members and to a demographically representative group of ACOGmembers known as the Collaborative Ambulatory Research Network (CARN). Responses were not significantly different for the random and CARN groups for most questions (p value shown when different). Results: Among 768 US practicing ACOG members surveyed, 364 (47%) responded. Seven per cent (CARN 10%, random 5%) had diagnosed one or more case(s) of acute toxoplasmosis in the past year. Respondents were well-informed about how to prevent toxoplasmosis. However, only 12% (CARN 11%, random 12%) indicated that a positive Toxoplasma IgM test might be a false–positive result, and only 11% (CARN 14%, random 9%) were aware that the Food and Drug Administration sent an advisory to all ACOG members in 1997 stating that some Toxoplasma IgM test kits have high false–positive rates. Most of those surveyed (CARN 70%, random 59%; X(2) p < 0.05) were opposed to universal screening of pregnant women. Conclusions: Many US obstetrician-gynecologists will encounter acute toxoplasmosis during their careers, but they are frequently uncertain about interpretation of the laboratory tests for the disease. Most would not recommend universal screening of pregnant women

    Effect of pioglitazone treatment in a patient with secondary multiple sclerosis

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    BACKGROUND: Ligands of the peroxisome proliferator-activated receptor-gamma (PPARγ) induce apoptosis in activated T-lymphocytes and exert anti-inflammatory effects in glial cells. Preclinical studies have shown that the thiazolidinedione pioglitazone, an FDA-approved PPARγ agonist used to treat type 2 diabetes, delays the onset and reduces the severity of clinical symptoms in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS). We therefore tested the safety and therapeutic potential of oral pioglitazone in a patient with secondary MS. CASE PRESENTATION: The rationale and risks of taking pioglitazone were carefully explained to the patient, consent was obtained, and treatment was initiated at 15 mg per day p.o. and then increased by 15 mg biweekly to 45 mg per day p.o. for the duration of the treatment. Safety was assessed by measurements of metabolic profiles, blood pressure, and edema; effects on clinical symptoms were assessed by measurement of cognition, motor function and strength, and MRI. Within 4 weeks the patient exhibited increased appetite, cognition and attention span. After 12 months treatment, body weight increased from 27.3 to 35.9 kg (32%) and maintained throughout the duration of the study. Upper extremity strength and coordination improved, and increased fine coordination was noted unilaterally after 8 months and bilaterally after 15 months. After 8 months therapy, the patient demonstrated improvement in orientation, short-term memory, and attention span. MRIs carried out after 10 and 18 months of treatment showed no perceptible change in overall brain atrophy, extent of demyelination, or in Gd-enhancement. After 3.0 years on pioglitazone, the patient continues to be clinically stable, with no adverse events. CONCLUSIONS: In a patient with secondary progressive MS, daily treatment with 45 mg p.o. pioglitazone for 3 years induced apparent clinical improvement without adverse events. Pioglitazone should therefore be considered for further testing of therapeutic potential in MS patients

    Trends in Veno-Arterial Extracorporeal Life Support With and Without an Impella or Intra-Aortic Balloon Pump for Cardiogenic Shock

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    Background: Mechanical circulatory support devices, such as the intra-aortic balloon pump (IABP) and Impella, are often used in patients on veno-arterial extracorporeal life support (VA-ECLS) with cardiogenic shock despite limited supporting clinical trial data. Methods and Results: Hospitalizations for cardiogenic shock from 2016 to 2018 were identified from the National Inpatient Sample. Trends in the use of VA-ECLS with and without an IABP or Impella were assessed semiannually. Multivariable logistic regression and general linear regression evaluated the association of Impella and IABP use with in-hospital outcomes. Overall, 12 035 hospitalizations with cardiogenic shock and VA-ECLS were identified, of which 3115 (26%) also received an IABP and 1880 (16%) an Impella. Use of an Impella with VA-ECLS substantially increased from 10% to 18% over this period (P\u3c0.001), whereas an IABP modestly increased from 25% to 26% (P\u3c0.001). In-hospital mortality decreased 54% to 48% for VA-ECLS only, 61% to 58% for VA-ECLS with an Impella, and 54% to 49% for VA-ECLS with an IABP (P\u3c0.001 each). Most (57%) IABPs or Impellas were placed on the same day as VA-ECLS. After adjustment, there were no differences in in-hospital mortality or length of stay with the addition of an IABP or Impella compared with VA-ECLS alone. Conclusions: From 2016 to 2018 in the United States, use of an Impella and IABP with VA-ECLS significantly increased. More than half of Impellas and IABPs were placed on the same day as VA-ECLS, and the use of a second mechanical circulatory support device did not impact in-hospital mortality. Further studies are needed to decipher the optimal timing and patient selection for this growing practice

    New cryptosporidium genotypes in HIV-infected persons.

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    Using DNA sequencing and phylogenetic analysis, we identified four distinct Cryptosporidium genotypes in HIV-infected patients: genotype 1 (human), genotype 2 (bovine) Cryptosporidium parvum, a genotype identical to C. felis, and one identical to a Cryptosporidium sp. isolate from a dog. This is the first identification of human infection with the latter two genotypes

    Prevalence of intestinal microsporidiosis in Human Immunodeficiency Virus-infected patients with diarrhea in major United States cities

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    To determine the prevalence of intestinal microsporidiosis in HIV-infected patients, we performed a prospective study of HIV-infected patients with diarrheal illnesses in three US hospitals and examined an observational database of HIV-infected patients in 10 US cities. Among 737 specimens from the three hospitals, results were positive for 11 (prevalence 1.5%); seven (64%) acquired HIV through male-to-male sexual contact, two (18%) through male-to-male sexual contact and injection drug use, and one (9%) through heterosexual contact; one (9%) had an undetermined mode of transmission. Median CD4 count within six months of diagnosis of microsporidiosis was 33 cells/µL (range 3 to 319 cells/µL). For the national observational database (n = 24,098), the overall prevalence of microsporidiosis was 0.16%. Prevalence of microsporidiosis among HIV-infected patients with diarrheal disease is low, and microsporidiosis is most often diagnosed in patients with very low CD4+ cell counts. Testing for microsporidia appears to be indicated, especially for patients with very low CD4+ cell counts.Para determinar a prevalência de microsporidiose intestinal em pacientes infectados pelo HIV foi realizado um estudo prospectivo em três hospitais dos Estados Unidos da América do Norte (EUA) e analizada uma base de dados nacional composta de dados coletados de pacientes infectados pelo HIV em 10 cidades dos EUA. De um total de 737 amostras de fezes de pacientes infectados pelo HIV que apresentavam diarréia, amostras de 11 pacientes (prevalência de 1,5%) foram positivas para microsporídios. Todos os positivos eram do sexo masculino e, entre eles, sete (64%) pacientes adquiriram a infecção pelo HIV através de relação homossexual, dois (18%) através de relação sexual e drogas injetáveis e um (9%) através de contato heterosexual, enquanto que em um paciente o modo de transmissão do HIV não foi determinado. A contagem média de linfócitos CD4 realizada até seis meses do diagnóstico de microsporidiose foi de 33 células/microlitro (3 a 319 células/microlitro). A análise da base de dados nacional (n = 24.098) mostrou uma prevalência de microsporidiose de 0,16%. A prevalência de microsporidiose em pacientes HIV-positivos com diarréia é baixa. Entretando, como a microsporidiose é mais frequentemente diagnosticada em pacientes com contagens de CD4 muito baixas, a indicação de pesquisa de microsporídios é justificada, especialmente para estes pacientes

    The multi-facets of sustainable nanotechnology : lessons from a nanosafety symposium

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    An international symposium for nanosafety was held recently at the Nanyang Technological University in Singapore. Topics relating to understanding nanomaterial properties, tools, and infrastructure required for predicting hazardous outcomes, measuring nanomaterial exposure levels, systems approach for risk assessment and public's perception of nanotechnology were covered. The need for a multidisciplinary approach, across both natural and social sciences, for developing sustainable nanotechnology solutions was heavily emphasized. This commentary highlights the major issues discussed and the commitment of the nanosafety research community in Singapore to contribute collectively to realise the vision of sustainable nanotechnology

    BreakTrans: Uncovering the genomic architecture of gene fusions

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    Producing gene fusions through genomic structural rearrangements is a major mechanism for tumor evolution. Therefore, accurately detecting gene fusions and the originating rearrangements is of great importance for personalized cancer diagnosis and targeted therapy. We present a tool, BreakTrans, that systematically maps predicted gene fusions to structural rearrangements. Thus, BreakTrans not only validates both types of predictions, but also provides mechanistic interpretations. BreakTrans effectively validates known fusions and discovers novel events in a breast cancer cell line. Applying BreakTrans to 43 breast cancer samples in The Cancer Genome Atlas identifies 90 genomically validated gene fusions. BreakTrans is available at http://bioinformatics.mdanderson.org/main/BreakTran
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