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ABSTRACT: The COVID-19 pandemic has had extensive impacts on mental health care delivery. Anecdotal observations of inpatient care teams at Pennsylvania Psychiatric Institute suggested increased patient acuity during the pandemic. The authors found no consensus definition for measuring psychiatric acuity in the literature. We performed an interrupted time series analysis to identify whether COVID-19 was associated with changes in several hospital parameters that might reflect our patients' access to psychiatric services and acuity. We found increases in inpatient parameters for length of stay, rates of involuntary admissions, and the incidence of restraints, seclusion, and 1:1 observation orders. Observing these increasing trends can inform mitigation efforts to improve the quality of mental health care treatment and care delivery. We suggest the use of these metrics for objective measurements of psychiatric acuity.
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COVID-19 , Trastornos Mentales , Humanos , COVID-19/epidemiología , Hospitales Psiquiátricos , Pandemias , Hospitalización , Atención a la Salud , Trastornos Mentales/epidemiología , Trastornos Mentales/terapiaRESUMEN
Individuals with mental illness often face barriers to voting. One of the primary barriers is not being registered to vote. This paper describes voter support activities (VSAs) provided to hospitalized adults on the acute inpatient psychiatric units at Pennsylvania Psychiatric Institute. During the six weeks preceding the 2020 general election, adult inpatients were offered six VSAs and an optional survey examining previous voting behaviors and barriers encountered to voting. VSAs included checking voter registration status and polling location, completing a paper or electronic voter registration application, and requesting a mail-in ballot. Of 189 patients approached, 119 individuals participated in the survey and 60 individuals utilized at least one VSA. This project demonstrates that VSAs are a welcome and feasible resource for psychiatrically hospitalized adults. Psychiatric providers can serve an important role in promoting access to voting-related activities for their patients.
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Equidad en Salud , Trastornos Mentales , Adulto , Humanos , Pacientes Internos , Política , Trastornos Mentales/terapia , PennsylvaniaRESUMEN
Background: The Society of Interdisciplinary Placebo Studies (SIPS) was one of many organizations that hosted a virtual scientific conference in response to the COVID-19 pandemic restrictions. Retaining essential benefits of an in-person conference experience was a primary objective for the SIPS conference planning committee and guided the selection of a virtual platform on which to host the 2021 meeting. This article reports on the methods used to design and analyze an engaging, virtual scientific conference, along with the findings and implications for future meetings. Methods: Participant use of and interaction with different features of the conference platform were recorded and exported for analysis. Additionally, all SIPS conference attendees were invited to complete a brief, online post-conference survey that inquired about their perceptions of the SIPS conference specifically as well as their opinions of virtual and hybrid conferences in general. Using these data, we assessed (1) attendance patterns, (2) level of engagement, and (3) attendee satisfaction. Results: The platform recorded 438 unique, active conference attendees who used either a mobile app, web browser, or both to participate during the 3-day program. Seventy-four percent (N = 324) of active users attended all 3 days with 30 and 26 new attendees on Days 2 and 3, respectively. The connections feature offered on the platform was the most utilized function within the online forum. Attendance in the parallel workshop sessions remained constant across the 3 days, with an average of 44.6% (SD = 6.77) of people moving between workshops within a single session. The two poster sessions had an average of 47.6 (SD = 17.97) and 27.8 (SD = 10.24) unique views per poster, respectively. Eleven percent (N = 48) of attendees completed the post-conference survey. Thirty-six percent of these responders stated they were only able to attend because the conference was offered virtually. Further, the quality of the conference had an average satisfaction rating of 68.08 out of 100 (SD = 22.94). Conclusion: Results of data analyses suggest the virtual platform allowed for those who were unable to attend to join virtually, produced moderate engagement throughout the conference, and that the majority of attendees were satisfied with the quality of the fully-virtual conference. Therefore, incorporating virtual aspects in future in-person conferences could enhance conference experience and participation.
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Mood dysregulation is a common feature in the psychopathology of people with intellectual disability (ID) and co-occurring behavioral/psychiatric disorders. It can present with a host of dangerous behaviors, including aggression, self-injury, and property damage. There are special techniques that are used to assess these behaviors in people with ID, that can eventually inform an appropriate approach to pharmacologic and nonpharmacologic treatment. Two case studies are presented that illustrate the elements in the assessment and treatment of mood dysregulation in ID.
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Raw produce is increasingly recognized as a vehicle of human gastroenteritis. Non-typhoidal Salmonella, pathogenic Escherichia coli, and other human pathogens have been isolated from fruits and vegetables in the field and in the marketplace, which led to the hypothesis that these microbes can use plants as alternate hosts. However, environmental and physiological factors that facilitate persistence of these bacteria in the crop production environment and make produce more vulnerable to post-harvest contamination have not been fully delineated. This study tested the effect of irrigation regimes on the susceptibility of peppers and tomatoes to post-harvest proliferation of Salmonella. The experiments were carried out over three experimental seasons in two locations using seven strains of Salmonella. The irrigation regime per se did not affect susceptibility of tomatoes and peppers to post-harvest proliferation of Salmonella; however, in some of the seasons, irrigation regime-dependent differences were observed. Red peppers and tomatoes were more conducive to proliferation of Salmonella than green fruit in all seasons. Inter-seasonal differences were the strongest factors affecting proliferation of Salmonella in peppers.
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Riego Agrícola/métodos , Capsicum/microbiología , Salmonella enterica/crecimiento & desarrollo , Solanum lycopersicum/microbiología , Verduras/microbiología , Capsicum/crecimiento & desarrollo , Contaminación de Alimentos/análisis , Frutas/crecimiento & desarrollo , Frutas/microbiología , Solanum lycopersicum/crecimiento & desarrollo , Estaciones del Año , Verduras/crecimiento & desarrolloRESUMEN
Fresh fruits and vegetables are increasingly recognized as important reservoirs of human pathogens, and therefore, significant attention has been directed recently to understanding mechanisms of the interactions between plants and enterics, like Salmonella. A screen of tomato cultivars for their susceptibility to Salmonella revealed significant differences in the ability of this human pathogen to multiply within fruits; expression of the Salmonella genes (cysB,â agfB,â fadH) involved in the interactions with tomatoes depended on the tomato genotype and maturity stage. Proliferation of Salmonella was strongly reduced in the tomato mutants with defects in ethylene synthesis, perception and signal transduction. While mutation in the ripening-related ethylene receptor Nr resulted only in a modest reduction in Salmonella numbers within tomatoes, strong inhibition of the Salmonella proliferation was observed in rin and nor tomato mutants. RIN and NOR are regulators of ethylene synthesis and ripening. A commercial tomato variety heterozygous for rin was less susceptible to Salmonella under the greenhouse conditions but not when tested in the field over three production seasons.
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Etilenos/inmunología , Enfermedades de las Plantas/microbiología , Salmonella/fisiología , Solanum lycopersicum/microbiología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Solanum lycopersicum/genética , Solanum lycopersicum/inmunología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Salmonella/genéticaRESUMEN
Fresh fruits and vegetables are increasingly recognized as vehicles of salmonellosis. Pre- and post-harvest environmental conditions, and physiological, and genetic factors are thought to contribute to the ability of human pathogens to persist in the production environment, attach to, colonize and proliferate in and on raw produce. How field production conditions affect the post-harvest food safety outcomes is not entirely understood. This study tested how varying nitrogen and potassium fertilization levels affected the "susceptibility" of tomatoes to Salmonella infections following the harvest of fruits. Two tomato varieties grown over three seasons under high, medium, and low levels of nitrogen and potassium fertilization in two locations were inoculated with seven strains of Salmonella. Even though the main effects of nitrogen and potassium fertilization on the susceptibility of tomatoes to infections with Salmonella enterica were not statistically significant overall, differences in nitrogen concentrations in plant tissues correlated with the susceptibility of partially ripe tomatoes (cv. Solar Fire) to Salmonella. Tomato maturity and the season in which tomatoes were produced had the strongest effect on the ability of Salmonella to multiply in tomatoes. Tomato phenolics, accumulation of which is known to correlate with rates of the N fertilization, did not inhibit growth of Salmonella in vitro.
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Fertilizantes/análisis , Frutas/microbiología , Nitrógeno/metabolismo , Potasio/metabolismo , Salmonella enterica/crecimiento & desarrollo , Solanum lycopersicum/microbiología , Proliferación Celular , Contaminación de Alimentos/análisis , Frutas/química , Frutas/crecimiento & desarrollo , Frutas/metabolismo , Solanum lycopersicum/química , Solanum lycopersicum/crecimiento & desarrollo , Solanum lycopersicum/metabolismo , Factores de TiempoRESUMEN
MAIN OBJECTIVES: Fresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest. EXPERIMENTAL DESIGN: Fruits from three tomato varieties, grown over three production seasons in two Florida locations, were infected with seven strains of Salmonella and their ability to multiply post-harvest in field-grown tomatoes was tested. The field experiments were set up as a two-factor factorial split plot experiment, with the whole-plot treatments arranged in a randomized complete-block design. The irrigation treatment (at three levels) was the whole-plot factor, and the split-plot factor was tomato variety, with three levels. The significance of the main, two-way, and three-way interaction effects was tested using the (type III) F-tests for fixed effects. Mean separation for each significant fixed effect in the model was performed using Tukey's multiple comparison testing procedure. MOST IMPORTANT DISCOVERIES AND SIGNIFICANCE: The irrigation regime per se did not affect susceptibility of the crop to post-harvest proliferation of Salmonella. However, Salmonella grew significantly better in water-congested tissues of green tomatoes. Tomato maturity and genotype, Salmonella genotype, and inter-seasonal differences were the strongest factors affecting proliferation. Red ripe tomatoes were significantly and consistently more conducive to proliferation of Salmonella. Tomatoes harvested in the driest, sunniest season were the most conducive to post-harvest proliferation of the pathogen. Statistically significant interactions between production conditions affected post-harvest susceptibility of the crop to the pathogen. UV irradiation of tomatoes post-harvest promoted Salmonella growth.
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Contaminación de Alimentos/prevención & control , Frutas/microbiología , Intoxicación Alimentaria por Salmonella/prevención & control , Salmonella enterica/crecimiento & desarrollo , Solanum lycopersicum/microbiología , Riego Agrícola/métodos , Técnicas de Tipificación Bacteriana , Manipulación de Alimentos/métodos , Microbiología de Alimentos , Genotipo , Humanos , Salmonella enterica/clasificación , Salmonella enterica/genética , Estaciones del Año , Rayos UltravioletaRESUMEN
Enteric pathogens, including non-typhoidal Salmonella spp. and enterovirulent Escherichia coli, are capable of persisting and multiplying within plants. Yet, little is still known about the mechanisms of these interactions. This study identified the Salmonella yihT gene (involved in synthesis of the O-antigen capsule) as contributing to persistence in immature tomato fruit. Deletion of yihT reduced competitive fitness of S. enterica sv. Typhimurium in green (but not ripe, regardless of color) tomato fruit by approximately 3 logs. The yihT recombinase-based in vivo expression technology (RIVET) reporter was strongly activated in unripe tomato fruit, and fitness of the mutant inversely correlated with the level of the yihT gene expression. Expression of yihT in mature tomato fruit was low, and yihT did not affect competitive fitness within mature fruit. To better understand the molecular basis of the phenotype, behaviors of the yihT RIVET reporter and the yihT mutant were tested in tomato fruit defective in ethylene signaling. These experiments suggest a role for functional ethylene-mediated signaling in the persistence of Salmonella spp. within tomato fruit. Furthermore, jasmonic acid and its precursors strongly reduced expression of yihT.
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Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica , Antígenos O/metabolismo , Enfermedades de las Plantas/microbiología , Salmonella typhimurium/metabolismo , Solanum lycopersicum/microbiología , Proteínas Bacterianas/metabolismo , Ciclopentanos/metabolismo , Etilenos/metabolismo , Frutas/microbiología , Expresión Génica , Genes Reporteros , Interacciones Huésped-Patógeno , Solanum lycopersicum/crecimiento & desarrollo , Solanum lycopersicum/metabolismo , Oxilipinas/metabolismo , Fenotipo , Reguladores del Crecimiento de las Plantas/metabolismo , Recombinación Genética , Salmonella typhimurium/genética , Salmonella typhimurium/fisiología , Eliminación de Secuencia , Transducción de SeñalRESUMEN
Proliferation of human enteric pathogens within alternate hosts, like plants, leads to temporal changes in gene expression and also selects for the phenotypic variants of the enterics that are presumed to be more fit within plants. Human enteric pathogens recovered from produce-borne outbreaks exhibit peculiar phenotypes, for example many of them do not display the rdar (red dry and rough) phenotype. The non-rdar phenotype results from mutations in cellulose and/or curli synthesis or regulation. How often these mutants arise, and whether they are more fit within plants is not entirely clear. We addressed this hypothesis by sequentially passaging the type strain of Salmonella enterica sv. Typhimurium ATCC14028 through tomatoes. Two spontaneous mutants defective in their ability to form red dry and rough colonies were further characterized. Even though attachment of the mutants to tomato surfaces was modestly reduced, they were 5- to 50-fold more competitive than the wild-type inside tomato fruits. Because the mutants were outcompeted by the wild-type on common laboratory media, and not in tomatoes, the lack of the rdar phenotype is probably beneficial within tomatoes. Recombinase-based in vivo expression tests indicate that the agfB and yihT genes were regulated differently in the mutants, although the corresponding mutations cannot fully account for the increased competitive fitness of the mutants. One of the variants has a mutated rpoS, which also reduced the expression of a SPI-5 effector encoded by sopB. A survey of the Salmonella strains recovered from produce outbreaks revealed that some were similarly non-rdar, likely containing rpoS mutations. This report indicates that the 'perfect storm' scenario, typically used to model outbreaks of produce-borne gastroenteritis, needs to account for the ability of the pathogen to rapidly evolve and adapt to the crop production environments.
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BACKGROUND: Recent outbreaks of vegetable-associated gastroenteritis suggest that enteric pathogens colonize, multiply and persist in plants for extended periods of time, eventually infecting people. Genetic and physiological pathways, by which enterics colonize plants, are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: To better understand interactions between Salmonella enterica sv. Typhimurium and tomatoes, a gfp-tagged Salmonella promoter library was screened inside red ripe fruits. Fifty-one unique constructs that were potentially differentially regulated in tomato relative to in vitro growth were identified. The expression of a subset of these promoters was tested in planta using recombinase-based in vivo expression technology (RIVET) and fitness of the corresponding mutants was tested. Gene expression in Salmonella was affected by fruit maturity and tomato cultivar. A putative fadH promoter was upregulated most strongly in immature tomatoes. Expression of the fadH construct depended on the presence of linoleic acid, which is consistent with the reduced accumulation of this compound in mature tomato fruits. The cysB construct was activated in the fruit of cv. Hawaii 7997 (resistant to a race of Ralstonia solanacearum) more strongly than in the universally susceptible tomato cv. Bonny Best. Known Salmonella motility and animal virulence genes (hilA, flhDC, fliF and those encoded on the pSLT virulence plasmid) did not contribute significantly to fitness of the bacteria inside tomatoes, even though deletions of sirA and motA modestly increased fitness of Salmonella inside tomatoes. CONCLUSIONS/SIGNIFICANCE: This study reveals the genetic basis of the interactions of Salmonella with plant hosts. Salmonella relies on a distinct set of metabolic and regulatory genes, which are differentially regulated in planta in response to host genotype and fruit maturity. This enteric pathogen colonizes tissues of tomatoes differently than plant pathogens, and relies little on its animal virulence genes for persistence within the fruit.
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Frutas/crecimiento & desarrollo , Frutas/microbiología , Regulación Bacteriana de la Expresión Génica , Técnicas Genéticas , Salmonella enterica/genética , Solanum lycopersicum/crecimiento & desarrollo , Solanum lycopersicum/microbiología , Microbiología de Alimentos , Frutas/genética , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Genes Bacterianos/genética , Genotipo , Ácido Linoleico/farmacología , Solanum lycopersicum/genética , Mutación , Pigmentación , Regiones Promotoras Genéticas/genética , Seguridad , Salmonella enterica/efectos de los fármacos , Salmonella enterica/patogenicidad , Salmonella enterica/fisiología , Regulación hacia Arriba/efectos de los fármacosRESUMEN
In light of the large number of studies published since the 2004 update of Schizophrenia Patient Outcomes Research Team psychopharmacological treatment recommendations, we conducted an extensive literature review to determine whether the current psychopharmacological treatment recommendations required revision and whether there was sufficient evidence to warrant new treatment recommendations for prespecified outcomes of interest. We reviewed over 400 articles, which resulted in 16 treatment recommendations: the revision of 11 previous treatment recommendations and 5 new treatment recommendations. Three previous treatment recommendations were eliminated. There were 13 interventions and/or outcomes for which there was insufficient evidence for a treatment recommendation, and a statement was written to summarize the current level of evidence and identify important gaps in our knowledge that need to be addressed. In general, there was considerable consensus among the Psychopharmacology Evidence Review Group and the expert consultants. Two major areas of contention concerned whether there was sufficient evidence to recommend specific dosage ranges for the acute and maintenance treatment of first-episode and multi-episode schizophrenia and to endorse the practice of switching antipsychotics for the treatment of antipsychotic-related weight gain. Finally, there continue to be major gaps in our knowledge, including limited information on (1) the use of adjunctive pharmacological agents for the treatment of persistent positive symptoms or other symptom domains of psychopathology, including anxiety, cognitive impairments, depressive symptoms, and persistent negative symptoms and (2) the treatment of co-occurring substance or medical disorders that occur frequently in individuals with schizophrenia.
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Antipsicóticos/uso terapéutico , Medicina Basada en la Evidencia , Evaluación de Resultado en la Atención de Salud , Esquizofrenia/tratamiento farmacológico , Psicología del Esquizofrénico , Comités Consultivos , Antipsicóticos/efectos adversos , Terapia Combinada , Comorbilidad , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Humanos , Psicotrópicos/efectos adversos , Psicotrópicos/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , RecurrenciaRESUMEN
PURPOSE: The association between a diagnosis of depression after a thromboembolic event (TEE) and an increase in acute health care use was examined. METHODS: A cohort of Medicare beneficiaries who were 65 years of age and older, who resided in the community, and who also experienced a TEE was constructed from the 1997-2001 Medicare Current Beneficiary Survey. Beneficiaries were assessed for TEEs and depression using the International Classification of Diseases, 9th Revision, Clinical Modification codes listed on Medicare claims. Time to first emergency department (ED) visit, inpatient hospitalization, and outpatient hospital visit were assessed using Cox-proportional hazard models. Counts of offices visits were assessed using negative binomial-regression models. RESULTS: Of the 7051 elderly patients included in the analysis, the total number with a claim for depression within 6 months of having a TEE was 380 (5.4%), including 259 antidepressant users (68.2% of depressed elders) and 198 selective serotonin-reuptake inhibitor (SSRI) users (76.4% of antidepressant users). Over half of elders with a depression claim (52.4%) had an inpatient hospitalization within 12 months of having a TEE compared to one third of the entire study sample (36.4%). Depressed elders had a 51% greater risk of hospitalization, a 56% greater risk of ED visits, and a 19% greater risk of outpatient visits. Antidepressant use did not affect the findings and was not found to be associated with health care use. CONCLUSION: A claim for depression by Medicare patients was associated with the increased use of acute health care services, including hospitalizations and ED visits, in the 12 months following a TEE. Neither antidepressant use nor SSRI use was associated with an increase or reduction in risk of using such services.
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Antidepresivos/uso terapéutico , Atención a la Salud/estadística & datos numéricos , Depresión/etiología , Tromboembolia/complicaciones , Anciano , Anciano de 80 o más Años , Depresión/tratamiento farmacológico , Servicio de Urgencia en Hospital , Femenino , Hospitalización , Humanos , Masculino , Infarto del Miocardio/psicología , Modelos de Riesgos Proporcionales , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Tromboembolia/psicologíaRESUMEN
Purpose. Depression and antidepressant use may independently increase the risk of acute myocardial infarction and mortality in adults. However, no studies have looked at the effect of depression on a broader thrombotic event outcome, assessed antidepressant use, or evaluated elderly adults. Methods. A cohort of 7,051 community-dwelling elderly beneficiaries who experienced a thrombotic cardiovascular event (TCE) were pooled from the 1997 to 2002 Medicare Current Beneficiary Survey and followed for 12 months. Baseline characteristics, antidepressant utilization, and death were ascertained from the survey, while indexed TCE, recurrent TCE, and depression (within 6 months of indexed TCE) were taken from ICD-9 codes on Medicare claims. Time to death and first recurrent TCE were assessed using descriptive and multivariate statistics. Results. Of the elders with a depression claim, 71.6% had a recurrent TCE and 4.7% died within 12 months of their indexed TCE, compared to 67.6% and 3.9% of those elders without a depression claim. Of the antidepressant users, 72.6% experienced a recurrent TCE and 3.9% died, compared to 73.7% and 4.6% in the subset of selective serotonin reuptake inhibitor (SSRI) users. Depression was associated with a shorter time to death (P = .008) in the unadjusted analysis. However, all adjusted comparisons revealed no effect by depression, antidepressant use, or SSRI use. Conclusions. Depression was not associated with time to death or recurrent TCEs in this study. Antidepressant use, including measures of any antidepressant use and SSRI use, was not associated with shorter time to death or recurrent TCE.
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In the presence of gratuitous inducers, the lac operon of Escherichia coli exhibits bistability. Most models in the literature assume that the inducer enters the cell via the carrier (permease), and exits by a diffusion-like process. The diffusive influx and carrier efflux are neglected. However, analysis of the data shows that in non-induced cells, the diffusive influx is comparable to the carrier influx, and in induced cells, the carrier efflux is comparable to the diffusive efflux. Since bistability entails the coexistence of steady states corresponding to both non-induced and induced cells, neither one of these fluxes can be ignored. We present a model accounting for both fluxes, and show that: (1) The thresholds (i.e., the extracellular inducer levels at which transcription turns on or off) are profoundly affected by both fluxes. The diffusive influx reduces the on threshold, and eliminates irreversible bistability, a phenomenon that is inconsistent with data. The carrier efflux increases the off threshold, and abolishes bistability at large permease activities, a conclusion that can be tested experimentally. (2) The thresholds are well approximated by simple analytical expressions obtained by considering two limiting cases (no carrier efflux and no diffusive influx). (3) The simulations are in good agreement with the data for isopropyl thiogalactoside (IPTG), but somewhat discrepant with respect to the data for thiomethyl galactoside (TMG). We discuss the potential sources of the discrepancy.
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Simulación por Computador , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica , Operón Lac , Modelos Genéticos , Activación Transcripcional/fisiología , Transporte Biológico , Expresión Génica , Isopropil Tiogalactósido/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Metilgalactósidos/metabolismo , Tiogalactósidos/metabolismoRESUMEN
During batch growth on mixtures of two growth-limiting substrates, microbes consume the substrates either sequentially (diauxie) or simultaneously. The ubiquity of these growth patterns suggests that they may be driven by a universal mechanism common to all microbial species. Recently, we showed that a minimal model accounting only for enzyme induction and dilution, the two processes that occur in all microbes, explains the phenotypes observed in batch cultures of various wild-type and mutant/recombinant cells (Narang and Pilyugin in J. Theor. Biol. 244:326-348, 2007). Here, we examine the extension of the minimal model to continuous cultures. We show that: (1) Several enzymatic trends, attributed entirely to cross-regulatory mechanisms, such as catabolite repression and inducer exclusion, can be quantitatively explained by enzyme dilution. (2) The bifurcation diagram of the minimal model for continuous cultures, which classifies the substrate consumption pattern at any given dilution rate and feed concentrations, provides a precise explanation for the empirically observed correlations between the growth patterns in batch and continuous cultures. (3) Numerical simulations of the model are in excellent agreement with the data. The model captures the variation of the steady state substrate concentrations, cell densities, and enzyme levels during the single- and mixed-substrate growth of bacteria and yeasts at various dilution rates and feed concentrations. This variation is well approximated by simple analytical expressions that furnish deep physical insights. (4) Since the minimal model describes the behavior of the cells in the absence of cross-regulatory mechanisms, it provides a rigorous framework for quantifying the effect of these mechanisms. We illustrate this by analyzing several data sets from the literature.
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Bacterias/crecimiento & desarrollo , Bacterias/genética , Reactores Biológicos/microbiología , Regulación Bacteriana de la Expresión Génica , Levaduras/crecimiento & desarrollo , Levaduras/genética , Bacterias/enzimología , Técnicas de Cultivo de Célula , Inducción Enzimática/genética , Represión Enzimática/genética , Metabolismo/genética , Levaduras/enzimologíaRESUMEN
OBJECTIVE: To examine racial and ethnic disparities in new prescription drug use. DATA SOURCES/STUDY SETTING: Secondary data analyses of the Medical Expenditure Panel Survey (1996-2001), a national survey representative of U.S. noninstitutionalized civilian population. Drug approval dates were from the GenRx database of Mosby. STUDY DESIGN: A negative binomial model was used to compare annual number of times when new drugs were obtained across racial and ethnic groups. Covariates in the model were demographic, economic characteristics, and health status. Drugs were considered new if approved within the past 5 years. We compared non-Hispanic whites with non-Hispanic blacks, and non-Hispanic whites with Hispanic whites, respectively, to examine racial and ethnic disparities separately. PRINCIPAL FINDINGS: Descriptive analyses found smaller racial disparities than ethnic disparities: the average annual number of times when new drugs were obtained was higher among non-Hispanic whites than non-Hispanic blacks (1.71 versus 1.36; p<.01) and Hispanic whites (1.71 versus 1.11; p<.01). Multivariate analyses found smaller ethnic than racial disparities: the number was 22-33 percent lower among non-Hispanic blacks than non-Hispanic whites (significant), and 5-16 percent lower among Hispanic whites than non-Hispanic whites (not always significant), respectively. While the absolute racial disparities decreased over the early years of the life cycles of the products, the reduction in disparities over time was not significant. CONCLUSIONS: There are racial disparities in the use of new medications, which persist during the first 5 years of marketing. Socioeconomic and health characteristics account for a larger share of ethnic disparities than racial disparities.