John D. Roberts

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Several single-base substitution mutations have been introduced into the lacZ alpha gene in cloning vector M13mp2, at 40-60% efficiency, in a rapid procedure requiring only transfection of the unfractionated products of standard in vitro mutagenesis reactions. Two simple additional treatments of the DNA, before transfection, produce a site-specific mutation(More)
A study was conducted to determine the fidelity of DNA synthesis catalyzed in vitro by the reverse transcriptase from a human immunodeficiency virus type 1 (HIV-1). Like other retroviral reverse transcriptases, the HIV-1 enzyme does not correct errors by exonucleolytic proofreading. Measurements with M13mp2-based fidelity assays indicated that the HIV-1(More)
A general repair process for DNA heteroduplexes has been detected in HeLa cell extracts. Using a variety of M13mp2 DNA substrates containing single-base mismatches and extra nucleotides, extensive repair is observed after incubation with HeLa cell cytoplasmic extracts and subsequent transfection of bacterial cells with the treated DNA. Most, but not all,(More)
BACKGROUND Sickle cell disease (SCD) is a chronic disease associated with high degrees of morbidity and increased mortality. Health-related quality of life (HRQOL) among adults with sickle cell disease has not been widely reported. METHODS We administered the Medical Outcomes Study 36-item Short-Form to 308 patients in the Pain in Sickle Cell Epidemiology(More)
OBJECTIVE Depression and anxiety are common in sickle cell disease (SCD) but relatively little is known about their impact on SCD adults. This study measured prevalence of depression and anxiety in SCD adults, and their effects on crisis and noncrisis pain, quality-of-life, opioid usage, and healthcare utilization. METHODS The Pain in Sickle Cell(More)
We determined the fidelity of avian myeloblastosis virus and Moloney murine leukemia virus reverse transcriptases (RTs) during DNA synthesis in vitro using the M13mp2 lacZ alpha gene as a mutational target. Both RTs commit an error approximately once for every 30,000 nucleotides polymerized. DNA sequence analysis of mutants generated in a forward mutation(More)
To examine combination cisplatin and twice-daily accelerated irradiation (RT) after aggressive transurethral resection of bladder tumor (TURBT) in an attempt to preserve the bladder and to determine the likelihood that patients who complete this regimen could then complete three cycles of methotrexate, cisplatin, vinblastine (MCV) chemotherapy. Between 1998(More)
BACKGROUND Researchers of sickle cell disease have traditionally used health care utilization as a proxy for pain and underlying vaso-occlusion. However, utilization may not completely reflect the amount of self-reported pain or acute, painful episodes (crises). OBJECTIVE To examine the prevalence of self-reported pain and the relationship among pain,(More)
The initiation of the morphogenesis of gustatory papillae is independent of innervation. To address the question of whether taste bud formation is associated with gustatory papilla morphogenesis, we examined developing tongues in mouse embryos from embryonic day 11 to birth. Despite the smooth morphological appearance of the lingual dorsal surface at 13(More)
The dietary cis-polyunsaturated fatty acid, arachidonic acid, stimulates adhesion of metastatic human breast carcinoma cells (MDA-MB-435) to the extracellular matrix, but the molecular mechanisms by which fatty acids modify the behavior of these cells are unclear. Exposure to arachidonic acid activates multiple signaling pathways. Activation of p38(More)