Medical Specialties Commons^™

Acquisition Of A Natural Resistance Gene Renders A Clinical Strain Of Methicillin-Resistant Staphylococcus Aureus Resistant To The Synthetic Antibiotic Linezolid, Seok-Ming Toh, Liqun Xiong, Cesar A Arias, Maria V Villegas, Karen Lolans, John Quinn, Alexander S Mankin

Faculty, Staff and Student Publications

Linezolid, which targets the ribosome, is a new synthetic antibiotic that is used for treatment of infections caused by Gram-positive pathogens. Clinical resistance to linezolid, so far, has been developing only slowly and has involved exclusively target site mutations. We have discovered that linezolid resistance in a methicillin-resistant Staphylococcus aureus hospital strain from Colombia is determined by the presence of the cfr gene whose product, Cfr methyltransferase, modifies adenosine at position 2503 in 23S rRNA in the large ribosomal subunit. The molecular model of the linezolid-ribosome complex reveals localization of A2503 within the drug binding site. The natural function of …

Quantitative Diffusion Tensor Imaging Detects Dopaminergic Neuronal Degeneration In A Murine Model Of Parkinson's Disease, Michael D Boska, Khader M Hasan, Danette Kibuule, Rebecca Banerjee, Erin Mcintyre, Jay A Nelson, Theresa Hahn, Howard E Gendelman, R Lee Mosley

Faculty, Staff and Student Publications

Early diagnosis of Parkinson's disease (PD) is required to improve therapeutic responses. Indeed, a clinical diagnosis of resting tremor, rigidity, movement and postural deficiencies usually reflect >50% loss of the nigrostriatal system in disease. In a step to address this, quantitative diffusion tensor magnetic resonance imaging (DTI) was used to assess nigrostriatal degeneration in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication model of dopaminergic nigral degeneration. We now demonstrate increased average diffusion (p

Time-Kill And Synergism Studies Of Ceftobiprole Against Enterococcus Faecalis, Including Beta-Lactamase-Producing And Vancomycin-Resistant Isolates, Cesar A Arias, Kavindra V Singh, Diana Panesso, Barbara E Murray

Faculty, Staff and Student Publications

Ceftobiprole (BAL9141) is an investigational cephalosporin with broad in vitro activity against gram-positive cocci, including enterococci. Ceftobiprole MICs were determined for 93 isolates of Enterococcus faecalis (including 16 beta-lactamase [Bla] producers and 17 vancomycin-resistant isolates) by an agar dilution method following the Clinical and Laboratory Standards Institute recommendations. Ceftobiprole MICs were also determined with a high inoculum concentration (10(7) CFU/ml) for a subset of five Bla producers belonging to different previously characterized clones by a broth dilution method. Time-kill and synergism studies (with either streptomycin or gentamicin) were performed with two beta-lactamase-producing isolates (TX0630 and TX5070) and two vancomycin-resistant isolates …

Short-Term Plasticity In A Computational Model Of The Tail-Withdrawal Circuit In Aplysia, Douglas A Baxter, John H Byrne

Faculty, Staff and Student Publications

The tail-withdrawal circuit of Aplysia provides a useful model system for investigating synaptic dynamics. Sensory neurons within the circuit manifest several forms of synaptic plasticity. Here, we developed a model of the circuit and investigated the ways in which depression (DEP) and potentiation (POT) contributed to information processing. DEP limited the amount of motor neuron activity that could be elicited by the monosynaptic pathway alone. POT within the monosynaptic pathway did not compensate for DEP. There was, however, a synergistic interaction between POT and the polysynaptic pathway. This synergism extended the dynamic range of the network, and the interplay between …

Surgical Versus Nonsurgical Treatment For Lumbar Degenerative Spondylolisthesis., James N Weinstein, Jon D Lurie, Tor D Tosteson, Brett Hanscom, Anna N A Tosteson, Emily A Blood, Nancy J O Birkmeyer, Alan Hilibrand, Harry Herkowitz, Frank P Cammisa, Todd J Albert, Sanford E Emery, Lawrence G Lenke, William A Abdu, Michael Longley, Thomas J Errico, Serena S Hu

Rothman Institute Papers

BACKGROUND: Management of degenerative spondylolisthesis with spinal stenosis is controversial. Surgery is widely used, but its effectiveness in comparison with that of nonsurgical treatment has not been demonstrated in controlled trials.

METHODS: Surgical candidates from 13 centers in 11 U.S. states who had at least 12 weeks of symptoms and image-confirmed degenerative spondylolisthesis were offered enrollment in a randomized cohort or an observational cohort. Treatment was standard decompressive laminectomy (with or without fusion) or usual nonsurgical care. The primary outcome measures were the Medical Outcomes Study 36-Item Short-Form General Health Survey (SF-36) bodily pain and physical function scores (100-point scales, …

Agrobacterium Para/Mind-Like Virc1 Spatially Coordinates Early Conjugative Dna Transfer Reactions, Krishnamohan Atmakuri, Eric Cascales, Oliver T Burton, Lois M Banta, Peter J Christie

Faculty, Staff and Student Publications

Agrobacterium tumefaciens translocates T-DNA through a polar VirB/D4 type IV secretion (T4S) system. VirC1, a factor required for efficient T-DNA transfer, bears a deviant Walker A and other sequence motifs characteristic of ParA and MinD ATPases. Here, we show that VirC1 promotes conjugative T-DNA transfer by stimulating generation of multiple copies per cell of the T-DNA substrate (T-complex) through pairwise interactions with the processing factors VirD2 relaxase, VirC2, and VirD1. VirC1 also associates with the polar membrane and recruits T-complexes to cell poles, the site of VirB/D4 T4S machine assembly. VirC1 Walker A mutations abrogate T-complex generation and polar recruitment, …

Dynamics Of A Minimal Model Of Interlocked Positive And Negative Feedback Loops Of Transcriptional Regulation By Camp-Response Element Binding Proteins, Hao Song, Paul Smolen, Evyatar Av-Ron, Douglas A Baxter, John H Byrne

Faculty, Staff and Student Publications

cAMP-response element binding (CREB) proteins are involved in transcriptional regulation in a number of cellular processes (e.g., neural plasticity and circadian rhythms). The CREB family contains activators and repressors that may interact through positive and negative feedback loops. These loops can be generated by auto- and cross-regulation of expression of CREB proteins, via CRE elements in or near their genes. Experiments suggest that such feedback loops may operate in several systems (e.g., Aplysia and rat). To understand the functional implications of such feedback loops, which are interlocked via cross-regulation of transcription, a minimal model with a positive and negative loop …

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Jss Editorial Board & Credits

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News In Brief

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Three Recent Gifts To The Department Of Surgery

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On The Job

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Innovative Therapies For Pancreatic-Related Cancers

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Resident Update: Where Are They Now?

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Acute Care Surgery Division Continues To Expand

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Overview: Nsqip Update

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Pancreatic Cancer: When The Stakes Are High . . .

Jefferson Surgical Solutions

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Clinical Presentation And Genotype Of Hepatitis Delta In Karachi, Tariq Moatter, Zaigham Abbas, Sabhita Shabir, Wasim Jafri

Department of Pathology and Laboratory Medicine

Aim:
To assess the clinical presentation and genotypes of delta hepatitis in local population.
Methods:
In this prospective study, 39 consecutive patients who were positive for HBsAg and hepatitis D virus (HDV) antibody were included. The patients were divided in two groups on the basis of presence or absence of HDV RNA and a comparative study was done. Genotype of HDV was determined in PCR positive patients.
Results:
Overall there is male dominance, in which 34 patients out of 39 (87.2%) were male. Twenty (51%) patients were from the adjacent areas of three provinces; Sindh, Punjab and Balochistan indicating the …

Chronic Administration Of Methylphenidate Produces Neurophysiological And Behavioral Sensitization, Pamela B Yang, Alan C Swann, Nachum Dafny

Faculty, Staff and Student Publications

The electrophysiological properties of acute and chronic methylphenidate (MPD) on neurons of the prefrontal cortex (PFC) and caudate nucleus (CN) have not been studied in awake, freely behaving animals. The present study was designed to investigate the dose-response effects of MPD on sensory evoked potentials recorded from the PFC and CN in freely behaving rats previously implanted with permanent electrodes, as well as their behavioral (locomotor) activities. On experimental day 1, locomotor behavior of rats was recorded for 2 h post-saline injection, and sensory evoked field potentials were recorded before and after saline and 0.6, 2.5, and 10 mg/kg, i.p., …

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Jss Editorial Board & Credits

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News In Brief

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A Legacy Of Leadership: Dr. Francis E. Rosato, Sr.

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On The Job

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Visualizing New Possibilities In Vascular Surgery

Jefferson Surgical Solutions

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Meet Our Surgical Interns

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Trends In Plastic And Reconstructive Surgery

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Overview From The Chairman

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Col. Darnell Waun's Second Chance At Life

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