OBJECTIVES:To define the spectrum of chronic noncancer pain treated with opioid medications in 2 primary care settings, and the prevalence of psychiatric comorbidity in this patient population. We also sought to determine the proportion of patients who manifested prescription opioid abuse behaviors and the factors associated with these behaviors. DESIGN:A retrospective cohort study. SETTING:A VA primary care clinic and an urban hospitalbased primary care center (PCC) located in the northeastern United States.PATIENTS: A random sample of VA patients (n = 50) and all PCC patients (n = 48) with chronic noncancer pain who received 6 or more months of opioid prescriptions during a 1-year period (April 1, 1997 through March 31, 1998) and were not on methadone maintenance. MEASUREMENTS:Information regarding patients' type of chronic pain disorder, demographic, medical, and psychiatric status, and the presence of prescription opioid abuse behaviors was obtained by medical record review.MAIN RESULTS: Low back pain was the most common disorder accounting for 44% and 25% of all chronic pain diagnoses in the VA and PCC samples, respectively, followed by injury-related (10% and 13%), diabetic neuropathy (8% and 10%), degenerative joint disease (16% and 13%), spinal stenosis (10% and 4%), headache (4% and 13%) and other chronic pain disorders (8% and 22%). The median duration of pain was 10 years (range 3 to 50 years) in the VA and 13 years in the PCC sample (range 1 to 49 years). Among VA and PCC patients, the lifetime prevalence rates of psychiatric comorbidities were: depressive disorder (44% and 54%), anxiety disorder (20% and 21%), alcohol abuse/dependence (46% and 31%), and narcotic abuse/dependence (18% and 38%). Prescription opioid abusive behaviors were recorded for 24% of VA and 31% of PCC patients. A lifetime history of a substance use disorder (adjusted odds ratio [OR], 3.8; 95% confidence interval [CI], 1.4 to 10.8) and age (adjusted OR, 0.94; 95% CI, 0.89 to 0.99) were independent predictors of prescription opioid abuse behavior. CONCLUSIONS:A broad spectrum of chronic noncancer pain disorders are treated with opioid medications in primary care settings. The lifetime prevalence of psychiatric comorbidity was substantial in our study population. A significant minority of patients manifested prescription opioid abusive behaviors, and a lifetime history of a substance use disorder and decreasing age were associated with prescription opioid abuse behavior. Prospective studies are needed to determine the potential benefits as well as risks associated with opioid use for chronic noncancer pain in primary care. C hronic noncancer pain is common in primary care settings and is often associated with substantial disability and distress.1±4 Depending on the source population, prevalence estimates for chronic noncancer pain range from 5% to 33% in primary care settings. 1,2 The costs associated with chronic noncancer pain are significant and include patient discomfort, decreased quality of life, and increased use of health ...

Bacteria can rapidly evolve resistance to antibiotics via the SOS response, a state of high-activity DNA repair and mutagenesis. We explore here the first steps of this evolution in the bacterium Escherichia coli. Induction of the SOS response by the genotoxic antibiotic ciprofloxacin changes the E. coli rod shape into multichromosome-containing filaments. We show that at subminimal inhibitory concentrations of ciprofloxacin the bacterial filament divides asymmetrically repeatedly at the tip. Chromosome-containing buds are made that, if resistant, propagate nonfilamenting progeny with enhanced resistance to ciprofloxacin as the parent filament dies. We propose that the multinucleated filament creates an environmental niche where evolution can proceed via generation of improved mutant chromosomes due to the mutagenic SOS response and possible recombination of the new alleles between chromosomes. Our data provide a better understanding of the processes underlying the origin of resistance at the single-cell level and suggest an analogous role to the eukaryotic aneuploidy condition in cancer.antibiotic resistance | SOS response | filamentation | mutation | evolution

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Computer based teaching and typical lecture sessions have similar educational gains.

To introduce DNA into E. coli cells Theory E. coli transformation is an important step that allows the introduction of heterologous DNA using plasmid vectors or introducing mutations via homologous recombination events. Equipment 4°C Centrifuge 42°C Water Bath 37°C Shaking Incubator

The fidelity of aminoacyl-tRNA selection by the ribosome depends on a conformational switch in the decoding center of the small ribosomal subunit induced by cognate but not by near-cognate aminoacyl-tRNA. The aminoglycosides paromomycin and streptomycin bind to the decoding center and induce related structural rearrangements that explain their observed effects on miscoding. Structural and biochemical studies have identified ribosomal protein S12 (as well as specific nucleotides in 16S ribosomal RNA) as a critical molecular contributor in distinguishing between cognate and near-cognate tRNA species as well as in promoting more global rearrangements in the small subunit, referred to as "closure." Here we use a mutational approach to define contributions made by two highly conserved loops in S12 to the process of tRNA selection. Most S12 variant ribosomes tested display increased levels of fidelity (a "restrictive" phenotype). Interestingly, several variants, K42A and R53A, were substantially resistant to the miscoding effects of paromomycin. Further characterization of the compromised paromomycin response identified a probable second, fidelity-modulating binding site for paromomycin in the 16S ribosomal RNA that facilitates closure of the small subunit and compensates for defects associated with the S12 mutations.

Small interfering RNAs (siRNAs) and microRNAs (miRNAs) bind to Argonaute family proteins to form a related set of effector complexes that play diverse roles in post-transcriptional gene regulation throughout the eukaryotic lineage. Here, sequence and structural analysis of the MID domain of the Argonaute proteins identified similarities with a family of allosterically regulated bacterial ligandbinding domains. In vitro and in vivo approaches were used to show that certain Argonaute proteins (those involved in translational repression) have conserved this functional allostery between two distinct sites, one involved in binding miRNA:target duplex and the other in binding the 5' cap feature (m 7 GpppG) of eukaryotic mRNAs. This allostery provides an explanation for how miRNA-bound effector complexes may avoid indiscriminate repressive action (mediated through binding interactions with the cap) prior to full target recognition. KeywordsArgonaute; miRNA; miRNP; m 7 GpppG cap; allostery Small interfering RNAs (siRNAs) and microRNAs (miRNAs) belong to an increasingly broad class of small, non-coding RNA molecules found in diverse organisms 1 . These two groups are broadly distinguished by their biogenesis pathways and their differential loading into distinct Argonaute complexes. siRNAs are generated in the cytoplasm and are loaded into an Argonaute-containing RNA-induced silencing complex (siRISC) to cleave targets with perfect complementarity. miRNAs are transcribed in the nucleus from a specific gene and are ultimately loaded into Argonaute-containing miRNPs (miRISC) that limit the expression of distinct mRNA targets with imperfect complementarity. And, though there are clearly shared molecular features for these two processes (e.g. an Argonaute protein and a small RNA), there are also distinct molecular features and players important both for small RNA loading and target recognition 2 . The Argonaute proteins are composed of several distinct domains with partially understood functions: an N-terminal domain, a PAZ domain that contains the binding site for the 3' end of the small RNA, a MID domain that contains the binding site for the 5' end of the small RNA (which will be the focus of discussion in this manuscript), and the PIWI domain that contains the catalytic center for the cleavage reaction that occurs during RNA interference (Fig. 1a).A number of molecular mechanisms have been proposed to account for the observed posttranscriptional control of miRNA-targeted genes including inhibition of translation initiation or elongation and the promotion of mRNA decay (reviewed in ref. 3). One previous studyCorrespondence should be addressed to R.G. (ragreen@jhmi.edu).. * These authors contributed equally to this work. Author InformationThe authors declare no competing financial interests. NIH Public Access Author ManuscriptNat Struct Mol Biol. Author manuscript; available in PMC 2010 March 8. RESULTS Argonaute MID domain analysis reveals functional groupingsThe mechanistic questions that arose from the studies b...

The chloramphenicol (Cm)-inducible emL4 gene of Tn1696 specifies nonenzymatic resistance to Cm and is regulated by attenuation.