Systematic approach for dissecting the molecular mechanisms of transcriptional regulation in bacteria.

Gene regulation is one of the most ubiquitous processes in biology. However, while the catalog of bacterial genomes continues to expand rapidly, we remain ignorant about how almost all of the genes in these genomes are regulated. At present, characterizing the molecular mechanisms by which individual regulatory sequences operate requires focused efforts using low-throughput methods. Here, we take a first step toward multipromoter dissection and show how a combination of massively parallel reporter assays, mass spectrometry, and information-theoretic modeling can be used to dissect multiple bacterial promoters in a systematic way. We show this approach on both well-studied and previously uncharacterized promoters in the enteric bacterium Escherichia coli In all cases, we recover nucleotide-resolution models of promoter mechanism. For some promoters, including previously unannotated ones, the approach allowed us to further extract quantitative biophysical models describing input-output relationships. Given the generality of the approach presented here, it opens up the possibility of quantitatively dissecting the mechanisms of promoter function in E. coli and a wide range of other bacteria.

Recurrent natural killer/T-cell lymphoma of the lacrimal sac and nasolacrimal duct in a 59-year-old Caucasian woman.

A 59-year-old Caucasian woman with past medical history significant for Natural Killer (NK)/T-cell lymphoma of the right nasal septum in remission for nine months presented after surveillance PET-CT imaging revealed increased metabolic activity in the right nasolacrimal duct. She also reported ipsilateral epiphora starting around this time. The lacrimal sac and nasolacrimal ductal mucosa were biopsied via an external approach. Pathologic evaluation revealed a proliferation of lymphoid cells with necrotic tissue. Immunohistochemical staining demonstrated predominantly CD3+, EBER+, and CD56+ cells indicating recurrent NK/T-cell lymphoma. This case describes an unusual presentation of recurrent NK/T-cell lymphoma involving the lacrimal excretory system in a Caucasian adult. Recurrent malignancy should be considered in the differential of any patient with a history of a lymphoproliferative disorder near the lacrimal drainage system who presents with new onset epiphora.

Intrinsically determined cell death of developing cortical interneurons.

Cortical inhibitory circuits are formed by γ-aminobutyric acid (GABA)-secreting interneurons, a cell population that originates far from the cerebral cortex in the embryonic ventral forebrain. Given their distant developmental origins, it is intriguing how the number of cortical interneurons is ultimately determined. One possibility, suggested by the neurotrophic hypothesis, is that cortical interneurons are overproduced, and then after their migration into cortex the excess interneurons are eliminated through a competition for extrinsically derived trophic signals. Here we characterize the developmental cell death of mouse cortical interneurons in vivo, in vitro and after transplantation. We found that 40% of developing cortical interneurons were eliminated through Bax (Bcl-2-associated X)-dependent apoptosis during postnatal life. When cultured in vitro or transplanted into the cortex, interneuron precursors died at a cellular age similar to that at which endogenous interneurons died during normal development. Over transplant sizes that varied 200-fold, a constant fraction of the transplanted population underwent cell death. The death of transplanted neurons was not affected by the cell-autonomous disruption of TrkB (tropomyosin kinase receptor B), the main neurotrophin receptor expressed by neurons of the central nervous system. Transplantation expanded the cortical interneuron population by up to 35%, but the frequency of inhibitory synaptic events did not scale with the number of transplanted interneurons. Taken together, our findings indicate that interneuron cell death is determined intrinsically, either cell-autonomously or through a population-autonomous competition for survival signals derived from other interneurons.

Distal Femoral Osteotomy for the Valgus Knee: Medial Closing Wedge Versus Lateral Opening Wedge: A Systematic Review.

PURPOSE: (1) To determine the radiographic correction/healing rate, patient-reported outcomes, reoperation rate, and complication rate after distal femoral osteotomy (DFO) for the valgus knee with lateral compartment pathology. (2) To summarize the reported results of medial closing wedge and lateral opening wedge DFO. METHODS: We conducted a systematic review of PubMed, MEDLINE, and CINAHL to identify studies reporting outcomes of DFOs for the valgus knee. Keywords included "distal femoral osteotomy," "chondral," "cartilage," "valgus," "joint restoration," "joint preservation," "arthritis," and "gonarthrosis." Two authors first reviewed the articles; our study exclusion criteria were then applied, and the articles were included on the basis relevance defined by the aforementioned criteria. The Methodological Index for Nonrandomized Studies scale judged the quality of the literature. Sixteen studies were relevant to the research questions out of 191 studies identified by the original search. RESULTS: Sixteen studies were identified reporting on 372 osteotomies with mean follow-up of 45 to 180 months. All studies reported mean radiographic correction to a near neutral mechanical axis, with 3.2% nonunion and 3.8% delayed union rates. There was a 9% complication rate and a 34% reoperation rate, of which 15% were converted to arthroplasty. There were similar results reported for medial closing wedge and lateral opening wedge techniques, with a higher conversion to arthroplasty in the medial closing wedge that was confounded by longer mean follow-up in this group (mean follow-up 100 v 58 months). CONCLUSIONS: DFOs for the valgus knee with lateral compartment disease provide improvements in patient-reported knee health-related quality of life at midterm follow-up but have high rates of reoperation. No evidence exists proving better results of either the lateral opening wedge or medial closing wedge techniques. LEVEL OF EVIDENCE: Level IV, systematic review of Level IV studies.

Tuning promoter strength through RNA polymerase binding site design in Escherichia coli.

One of the paramount goals of synthetic biology is to have the ability to tune transcriptional networks to targeted levels of expression at will. As a step in that direction, we have constructed a set of 18 unique binding sites for E. coli RNA Polymerase (RNAP) δ7° holoenzyme, designed using a model of sequence-dependent binding energy combined with a thermodynamic model of transcription to produce a targeted level of gene expression. This promoter set allows us to determine the correspondence between the absolute numbers of mRNA molecules or protein products and the predicted promoter binding energies measured in k(B)T energy units. These binding sites adhere on average to the predicted level of gene expression over 3 orders of magnitude in constitutive gene expression, to within a factor of 3 in both protein and mRNA copy number. With these promoters in hand, we then place them under the regulatory control of a bacterial repressor and show that again there is a strict correspondence between the measured and predicted levels of expression, demonstrating the transferability of the promoters to an alternate regulatory context. In particular, our thermodynamic model predicts the expression from our promoters under a range of repressor concentrations between several per cell up to over 100 per cell. After correcting the predicted polymerase binding strength using the data from the unregulated promoter, the thermodynamic model accurately predicts the expression for the simple repression strains to within 30%. Demonstration of modular promoter design, where parts of the circuit (such as RNAP/TF binding strength and transcription factor copy number) can be independently chosen from a stock list and combined to give a predictable result, has important implications as an engineering tool for use in synthetic biology.

Oral cancer: FAQ.

The efficacy of clinical examination in detecting intraoral malignances has recently been called into question, as it does not accurately predict the histological diagnosis. A brief reexamination of one study provides some insights into what this means to the clinician. Making a diagnosis on the basis of a clinical examination may result in a false-positive finding and unnecessary treatment. However, a more significant concern would be a false-negative finding, in which disease is present but not detected and therefore not treated. The most effective preventive strategy is to help patients reduce or eliminate dangerous habits, and to remain alert for signs of potentially malignant or early-stage lesions, and perform routine visual and tactile examinations of all patients. A working knowledge of the clinical epidemiology of oral cancer, familiarity with the risk factors, signs and symptoms, together with continued vigilance in the form of regular, systematic and thorough clinical examination remains the most basic means of ensuring early detection of oral cancer and providing the best care possible.

Oral cancer: FAQ.

The efficacy of clinical examination in detecting intraoral malignances has recently been called into question, as it does not accurately predict the histological diagnosis. A brief re-examination of one study provides some insights into what this means to the clinician. Making a diagnosis on the basis of a clinical examination may result in a false-positive finding and unnecessary treatment. However, a more significant concern would be a false-negative finding, in which disease is present but not detected and therefore not treated. The most effective preventive strategy is to help patients reduce or eliminate dangerous habits, and to remain alert for signs of potentially malignant or early-stage lesions, and perform routine visual and tactile examinations of all patients. A working knowledge of the clinical epidemiology of oral cancer, familiarity with the risk factors, signs and symptoms, together with continued vigilance in the form of regular, systematic and thorough clinical examination remains the most basic means of ensuring early detection of oral cancer and providing the best care possible.

Reduction of seizures by transplantation of cortical GABAergic interneuron precursors into Kv1.1 mutant mice.

Epilepsy, a disease characterized by abnormal brain activity, is a disabling and potentially life-threatening condition for nearly 1% of the world population. Unfortunately, modulation of brain excitability using available antiepileptic drugs can have serious side effects, especially in the developing brain, and some patients can only be improved by surgical removal of brain regions containing the seizure focus. Here, we show that bilateral transplantation of precursor cells from the embryonic medial ganglionic eminence (MGE) into early postnatal neocortex generates mature GABAergic interneurons in the host brain. In mice receiving MGE cell grafts, GABA-mediated synaptic and extrasynaptic inhibition onto host brain pyramidal neurons is significantly increased. Bilateral MGE cell grafts in epileptic mice lacking a Shaker-like potassium channel (a gene mutated in one form of human epilepsy) resulted in significant reductions in the duration and frequency of spontaneous electrographic seizures. Our findings suggest that MGE-derived interneurons could be used to ameliorate abnormal excitability and possibly act as an effective strategy in the treatment of epilepsy.

Management of the oral sequelae of cancer therapy.

Oral cancer and the oral sequelae of treatment for oral and other malignancies can significantly affect a patient's oral and systemic health, as well as have a profound impact on quality of life. Compromised oral health prior to, during, and following cancer therapy can affect treatment outcomes. Increasingly, dental professionals in the community are being called upon to provide care for these individuals. Radiation therapy is routinely used for tumors of the head and neck, delivering a concentrated radiation dose to the tumor, but also to the immediately surrounding tissue. Oral complications are related to the site radiated and the total radiation dose. Cancer chemotherapy is provided as a primary treatment for some cancers and as an adjunctive modality for other cancers. The goal is to eradicate the rapidly growing cells of the tumor, but chemotherapy is often toxic to other cells that rapidly divide normally including the oral mucosa. The use of combined chemotherapy and radiation is now considered standard for most locally advanced tumors of the head and neck. The toxicities of this combined therapy are essentially the same as with radiation alone, but develop more rapidly and are typically more severe when they reach maximum level. The most common oral sequelae of cancer treatment are: xerostomia, the sensation of a dry mouth as a result of damage to the salivary glands and/or medication; mucositis, the inflammation and ulceration of the oral mucosa; and infection as a result of the loss of mucosal integrity. Management of oral health during cancer therapy includes identifying at-risk patients, patient education, appropriate pretreatment interventions, and timely management of complications. Appropriate preventive and therapeutic measures will help minimize the risk of oral and associated systemic complications, improve treatment outcomes, and improve the patient's quality of life.

Deletion of Dlx1 results in reduced glutamatergic input to hippocampal interneurons.

Dlx transcription factors are important in the differentiation of GABAergic interneurons. In mice lacking Dlx1, early steps in interneuron development appear normal. Beginning at ∼ 1 mo of age, primarily dendrite-innervating interneuron subtypes begin to undergo apoptosis in Dlx1(-/-) mice; this is accompanied by a reduction in GABAergic transmission and late-onset epilepsy. The reported reduction of synaptic inhibition is greater than might be expected given that interneuron loss is relatively modest in Dlx1(-/-) mice. Here we report that voltage-clamp recordings of CA1 interneurons in hippocampal slices prepared from Dlx1(-/-) animals older than postnatal day 30 (>P30) revealed a significant reduction in excitatory postsynaptic current (EPSC) amplitude. No changes in EPSCs onto interneurons were observed in cells recorded from younger animals (P9-12). Current-clamp recordings from interneurons at these early postnatal ages showed that interneurons in Dlx1(-/-) mutants were immature and more excitable, although membrane properties normalized by P30. Terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling, caspase-3, and NeuN staining did not reveal frank cell damage or loss in area CA3 of hippocampal sections from adult Dlx1(-/-) mice. Delayed interneuron maturation may lead to interneuron hyperexcitability, followed by a compensatory reduction in the strength of excitatory transmission onto interneurons. This reduced excitation onto surviving interneurons, coupled with the loss of a significant fraction of GABAergic inputs to excitatory neurons starting at P30, may underlie cortical dysrhythmia and seizures previously observed in adult Dlx1(-/-) mice.

Treatment of nicotine dependence with Chantix (varenicline).

Varenicline is the generic name for Chantix, the newest drug available for the treatment of tobacco dependence. In a randomized controlled clinical trial, the abstinence rate at 1 year for patients using varencline was superior to that of patients in the group using bupropion SR (Zyban) and in the placebo group (11). Varenicline reduces nicotine withdrawal symptoms, cigarette craving and nicotine satisfaction. Post-market reports prompted a warning of serious adverse neuropsychiatric events in patients taking varenicline. As is the case with any surgical procedure and/or prescription medication, full disclosure of the risks and benefits should be discussed with the patient. The significant health benefits of quitting smoking should be weighed against the individual's risk of adverse events associated with the use of varenicline for smoking cessation.

Principles of evidence-based dental practice (EBDP).

In an effort to improve patient care, there has been a growing trend across the nation and the world to embed the principles of evidence-based dentistry into mainstream care delivery by private practicing dentists. Evidence-based dentistry is an essential tool that is used to improve the quality of care and to reduce the gap between what we know, what is possible, and what we do. An evidence-based health care practice is one that includes the decision maker's ability to find, assess, and incorporate high-quality, valid information in diagnosis and treatment. The evidence is considered in conjunction with the clinician's experience and judgment, and the patient's preferences, values, and circumstances. This article introduces the basic skills of evidence-based dentistry. Their practice requires a discipline of lifelong learning in which recent and relevant scientific evidence are translated into practical clinical applications.

The evidence-based dentistry initiative at Baylor College of Dentistry.

This report describes the impact of an R25 Oral Health Research Education Grant awarded to the Texas A&M Health Science Center-Baylor College of Dentistry (BCD) to promote the application of basic and clinical research findings to clinical training and encourage students to pursue careers in oral health research. At Baylor, the R25 grant supports a multi-pronged initiative that employs clinical research as a vehicle for acquainting both students and faculty with the tools of evidence-based dentistry (EBD). New coursework and experiences in all 4 years of the curriculum plus a variety of faculty development offerings are being used to achieve this goal. Progress on these fronts is reflected in a nascent "EBD culture" characterized by increasing participation and buy-in by students and faculty. The production of a new generation of dental graduates equipped with the EBD skill set as well as a growing nucleus of faculty who can model the importance of evidence-based practice is of paramount importance for the future of dentistry.

Humanistic and Economic Burden of Geographic Atrophy: A Systematic Literature Review.

PURPOSE: Geographic atrophy (GA), the advanced form of dry age-related macular degeneration, can result in irreversible blindness over time. We performed a systematic literature review to assess the humanistic and economic burden of GA. METHODS: Predefined search terms were used to identify studies in PubMed, Embase, and Cochrane Library; conference abstracts also were searched. RESULTS: Of 1111 unique studies identified, 25 studies on humanistic burden, 4 on economic burden, and 3 on both humanistic and economic burden of GA were included. Vision-related functioning and health-related quality of life (HRQOL) are poor in patients with GA. HRQOL is commonly measured using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25); patients with GA have significantly lower composite and subscale scores for near activities, distance activities, dependency, driving, social functioning, mental health, role difficulties, color vision, and peripheral vision than individuals without GA. Driving is a particular concern, and inability to drive affects dependency. Vision-related quality of life (VRQOL) declines as GA progresses. While we identified only 7 reports describing the economic burden of GA, its direct costs may be substantial. In a US study, mean cost to the payer per patient with GA was $11,533 in the year after diagnosis. A multinational study estimated annualized total direct costs of €1772 per patient with GA, mainly driven by diagnostic tests and procedures (€1071). Patients with GA are at increased risk of falls and fractures, potentially increasing direct costs. Only one study evaluated indirect costs, estimating ~$24.4 billion in yearly lost wages among people with severe vision loss due to GA or drusen ≥125 µm. CONCLUSION: GA represents a significant humanistic burden. Evidence on the economic impact of GA is limited; characterizing the economic burden of GA requires further research. Interventions that reduce GA-related disability may improve HRQOL and reduce indirect costs.

Transtendinous Rotator Cuff Tear Repair with Bone Marrow Aspirate Concentrate Dermal Allograft Augmentation.

Rotator cuff tears involving the musculotendinous junction with a significant amount of tendon still attached to the footprint laterally represent a challenging scenario for shoulder arthroscopists. Because of these challenges, adjunctive techniques to bridge tissue gaps may be required, and biologic augmentation may be considered to improve the healing environment. The following technique presents a stepwise approach to accomplishing the dual goals of a stable anatomic repair and biologic augmentation of this difficult pattern of rotator cuff pathology.

Subgroup analysis of clinical and MRI outcomes in participants with a first clinical demyelinating event at risk of multiple sclerosis in the ORACLE-MS study.

BACKGROUND: In the Phase 3, 96-week ORACLE-MS study, cladribine 10 mg tablets (3.5 mg/kg or 5.25 mg/kg cumulative dose over 2 years) significantly reduced the rate of conversion to clinically definite multiple sclerosis (CDMS) per the Poser criteria (henceforth referred to as CDMS), multiple sclerosis (MS) per the 2005 McDonald criteria, and the number of new or persisting T1 gadolinium-enhancing (Gd+), new or enlarging T2, and combined unique active (CUA) lesions versus placebo in participants with a first clinical demyelinating event (FCDE). Patient demographic and disease characteristics may be predictors of disease progression. The current study analyzed the effect of cladribine tablets in subgroups of participants in the ORACLE-MS study by baseline demographics and disease characteristics. METHODS: This analysis retrospectively examined data collected from 616 participants enrolled in the ORACLE-MS study (placebo, n=206; cladribine tablets 3.5 mg/kg, n=206; cladribine tablets 5.25 mg/kg, n=204). Five subgroups were predetermined by baseline demographics, including sex, age (<30 or ≥30 years), classification of FCDE, and lesion characteristics, including absence or presence of T1 Gd+ lesions and number of T2 lesions (<9 or ≥9). Selected endpoints of the ORACLE-MS study were re-analyzed for these subgroups. The primary and main secondary endpoints were time to conversion to CDMS and MS (2005 McDonald criteria), respectively. Secondary magnetic resonance imaging (MRI) endpoints included cumulative T1 Gd+ and new or enlarging T2 lesions. Cox proportional hazards models were used to evaluate time to conversion to CDMS and MS (2005 McDonald criteria). This analysis focused primarily on the results for the cladribine tablets 3.5 mg/kg group because this dosage is approved for relapsing forms of MS. RESULTS: In the overall intent-to-treat (ITT) population, cladribine tablets 3.5 mg/kg significantly reduced the risk of conversion to CDMS (hazard ratio [HR]=0.326; P<0.0001) and MS (2005 McDonald criteria; HR=0.485; P<0.0001) versus placebo. Similar effects of cladribine tablets on risk of conversion were observed in post hoc analyses of subgroups defined by various baseline characteristics. In both the ITT population and across subgroups, cladribine tablets 3.5 mg/kg reduced the numbers of cumulative T1 Gd+ (range of rate ratios: 0.106-0.399), new or enlarging T2 (range of rate ratios: 0.178-0.485), and CUA (range of rate ratios: 0.154-0.384) lesions versus placebo (all nominal P<0.03). Multivariate Cox proportional hazards models revealed that age (HR=0.577, nominal P<0.0001), FCDE classification (HR=0.738, nominal P=0.0043), presence of T1 Gd+ lesions (HR=0.554, nominal P<0.0001), and number of T2 lesions (HR=0.417, nominal P<0.0001) at baseline were factors associated with risk of conversion to MS (2005 McDonald criteria), whereas no baseline factors examined were associated with risk of conversion to CDMS. CONCLUSION: In this post hoc analysis of the ORACLE-MS study, cladribine tablets reduced the risk of conversion to multiple sclerosis and lesion burden in participants with an FCDE in the overall ITT population and multiple subgroups defined by baseline demographics and lesion characteristics.

Tobacco cessation education for dentists: an evaluation of the lecture format.

Dentists with tobacco cessation training perform more interventions, report increased self-efficacy, preparedness and fewer barriers than those without training. The aim of this study was to assess changes in knowledge, attitudes and behavior of dentists (CE group) at six months following presentation of a standardized tobacco cessation lecture module. These data were compared to those from age and gender-matched controls who did not receive training. The CE group was more likely to feel cessation was very important, score higher on knowledge questions, update tobacco use of continuing patients, ask former smokers about relapse and ask about daily consumption. The CE group was also more likely to discuss the personal relevance of quitting, roadblocks and setting quit dates, identify triggers, discuss pharmacotherapy and provide follow-up. These results suggest that group education appears to be a cost-efficient and effective method of teaching dentists about the latest methods of tobacco cessation.

Management of oropharyngeal mucositis pain.

Effective pain control for mucositis requires constant attention and willingness on the part of managing clinicians to evaluate and adapt pain-relieving strategies throughout the period of risk for oral mucositis. By utilizing the principles of an individualized, tiered approach to pain management that addresses the multidimensional components of a patient's pain, maximum comfort can be consistently provided while reducing the risk for side effects.

Smokeless tobacco: challenges, products and, cessation.

Tobacco companies continue to develop and aggressively market new products for oral use. Most new products are intended to dissolve in the mouth and swallow rather than spit out the juices. These products effectively circumvent smoke-free policies, decrease tobacco cessation efforts, and create individuals who use both smokeless tobacco (ST) and cigarettes. All ST products contain nicotine, carcinogens, and pose multiple health risks. The cancer and health risks associated with ST use extend well beyond the changes in the oral cavity and the risk of oral cancer. Unlike cigarettes, the contents of ST vary widely by brand and product posing difficulty in the use of the available pharmacotherapy for cessation. Although no uniform guidelines exist for the use of pharmacotherapy for smokeless tobacco cessation, research suggests that use of these drugs is effective. The most important motivator for quitting ST cessation remains in the hands of the dentist.

Arthroscopic Posterior Capsular Release for Loss of Knee Extension.

Arthrofibrosis, as a result of osteoarthritis, after trauma, or after knee surgery, can have significant implications for patient function, satisfaction, and outcomes. When extensive conservative management fails to achieve satisfactory results, surgical intervention may be necessary. Arthroscopic techniques to release anterior adhesions are often viewed as easier and safer than posterior releases required for flexion contractures. We present our technique of a safe, effective, and reproducible arthroscopic complete posterior capsulotomy.