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BACKGROUND: In 2015, the stillbirth rate after 28 weeks (late gestation) in Australia was 35% higher than countries with the lowest rates globally. Reductions in late gestation stillbirth rates have steadily improved in Australia. However, to amplify and sustain reductions, more needs to be done to reduce practice variation and address sub-optimal care. Implementing bundles for maternity care improvement in the UK have been associated with a 20% reduction in stillbirth rates. A similar approach is underway in Australia; the Safer Baby Bundle (SBB) with five elements: 1) supporting women to stop smoking in pregnancy, 2) improving detection and management of fetal growth restriction, 3) raising awareness and improving care for women with decreased fetal movements, 4) improving awareness of maternal safe going-to-sleep position in late pregnancy, 5) improving decision making about the timing of birth for women with risk factors for stillbirth. METHODS: This is a mixed-methods study of maternity services across three Australian states; Queensland, Victoria and New South Wales. The study includes evaluation of 'targeted' implementer sites (combined total approximately 113,000 births annually, 50% of births in these states) and monitoring of key outcomes state-wide across all maternity services. Progressive implementation over 2.5 years, managed by state Departments of Health, commenced from mid-2019. This study will determine the impact of implementing the SBB on maternity services and perinatal outcomes, specifically for reducing late gestation stillbirth. Comprehensive process, impact, and outcome evaluations will be conducted using routinely collected perinatal data, pre- and post- implementation surveys, clinical audits, focus group discussions and interviews. Evaluations explore the views and experiences of clinicians embedding the SBB into routine practice as well as women's experience with care and the acceptability of the initiative. DISCUSSION: This protocol describes the evaluation of the SBB initiative and will provide evidence for the value of a systematic, but pragmatic, approach to strategies to reduce the evidence-practice gaps across maternity services. We hypothesise successful implementation and uptake across three Australian states (amplified nationally) will be effective in reducing late gestation stillbirths to that of the best performing countries globally, equating to at least 150 lives saved annually. TRIAL REGISTRATION: The Safer Baby Bundle Study was retrospectively registered on the ACTRN12619001777189 database, date assigned 16/12/2019.
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Morte Fetal/prevenção & controle , Serviços de Saúde Materna/normas , Melhoria de Qualidade/organização & administração , Natimorto , Austrália , Feminino , Humanos , Lactente , Gravidez , Avaliação de Programas e Projetos de Saúde , Projetos de Pesquisa , Fatores de RiscoRESUMO
BACKGROUND: 'Bundles of care' are being implemented to improve key practice gaps in perinatal care. As part of our development of a stillbirth prevention bundle, we consulted with Australian maternity care providers. OBJECTIVE: To gain the insights of Australian maternity care providers to inform the development and implementation of a bundle of care for stillbirth prevention. METHODS: A 2018 on-line survey of hospitals providing maternity services included 55 questions incorporating multiple choice, Likert items and open text. A senior clinician at each site completed the survey. The survey asked questions about practices related to fetal growth restriction, decreased fetal movements, smoking cessation, intrapartum fetal monitoring, maternal sleep position and perinatal mortality audit. The objectives were to assess which elements of care were most valued; best practice frequency; and, barriers and enablers to implementation. RESULTS: 227 hospitals were invited with 83 (37%) responding. All proposed elements were perceived as important. Hospitals were least likely to follow best practice recommendations "all the time" for smoking cessation support (<50%), risk assessment for fetal growth restriction (<40%) and advice on sleep position (<20%). Time constraints, absence of clear guidelines and lack of continuity of carer were recognised as barriers to implementation across care practices. CONCLUSIONS: Areas for practice improvement were evident. All elements of care were valued, with increasing awareness of safe sleeping position perceived as less important. There is strong support from maternity care providers across Australia for a bundle of care to reduce stillbirth.
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Serviços de Saúde Materna/estatística & dados numéricos , Assistência Perinatal/estatística & dados numéricos , Morte Perinatal/prevenção & controle , Natimorto , Austrália , Estudos Transversais , Feminino , Movimento Fetal , Maternidades , Humanos , Gravidez , Inquéritos e QuestionáriosRESUMO
We present the detection of persistent soft X-ray radiation with Lx ~ 1041-1042 erg s-1 at the location of the extremely luminous, double-humped transient ASASSN-15lh as revealed by Chandra and Swift. We interpret this finding in the context of observations from our multiwavelength campaign, which revealed the presence of weak narrow nebular emission features from the host-galaxy nucleus and clear differences with respect to superluminous supernova optical spectra. Significant UV flux variability on short timescales detected at the time of the rebrightening disfavors the shock interaction scenario as the source of energy powering the long-lived UV emission, while deep radio limits exclude the presence of relativistic jets propagating into a low-density environment. We propose a model where the extreme luminosity and double-peaked temporal structure of ASASSN-15lh is powered by a central source of ionizing radiation that produces a sudden change in the ejecta opacity at later times. As a result, UV radiation can more easily escape, producing the second bump in the light curve. We discuss different interpretations for the intrinsic nature of the ionizing source. We conclude that, if the X-ray source is physically associated with the optical-UV transient, then ASASSN-15lh most likely represents the tidal disruption of a main-sequence star by the most massive spinning black hole detected to date. In this case, ASASSN-15lh and similar events discovered in the future would constitute the most direct probes of very massive, dormant, spinning, supermassive black holes in galaxies. Future monitoring of the X-rays may allow us to distinguish between the supernova hypothesis and the hypothesis of a tidal disruption event.
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While the influence of alkyl chain length and headgroup size on self-assembly behaviour has been well-established for simple surfactants, the rational control over the pH- and concentration-dependent self-assembly behaviour in stimuli responsive peptides remains an elusive goal. Here, we show that different amphiphilic peptides can have similar self-assembly phase diagrams, providing the relative strengths of the attractive and repulsive forces are balanced. Using palmitoyl-YYAAEEEEK(DO3A:Gd)-NH2 and palmitoyl-YAAEEEEK(DO3A:Gd)-NH2 as controls, we show that reducing hydrophobic attractive forces through fewer methylene groups in the alkyl chain will lead to a similar self-assembly phase diagram as increasing the electrostatic repulsive forces via the addition of a glutamic acid residue. These changes allow creation of self-assembled MRI vehicles with slightly different micelle and nanofiber diameters but with minimal changes in the spin-lattice T1 relaxivity. These findings reveal a powerful strategy to design self-assembled vehicles with different sizes but with similar self-assembly profiles.
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Peptídeos/química , Tensoativos/química , Dicroísmo Circular , Microscopia Eletrônica de Transmissão , Conformação Molecular , Peptídeos/síntese química , Tensoativos/síntese químicaRESUMO
OBJECTIVE: To explore the variation in hospital caesarean section (CS) rates for nulliparous women, to determine whether different case-mix, labour and delivery, and hospital factors can explain this variation and to examine the association between hospital CS rates and outcomes. DESIGN: Population-based cohort study. SETTING: New South Wales, 2009-2010. POPULATION: Nulliparous women with singleton cephalic live births at term. METHODS: Random effect multilevel logistic regression models using linked hospital discharge and birth data. MAIN OUTCOME MEASURES: Prelabour and intrapartum CS rates following spontaneous labour or labour induction; maternal and neonatal severe morbidity rates. RESULTS: Of 67 239 nulliparous women, 4902 (7.3%) had a prelabour CS, 39 049 (58.1%) laboured spontaneously, and 23 288 (34.6%) had labour induced. Overall, there were 18 875 (28.1%) CSs, with labour inductions twice as likely to result in an intrapartum CS compared with women with a spontaneous onset of labour (34.0% versus 15.5%). After adjusting for differences in case-mix, labour and delivery, and hospital factors, the overall variation in CS rates decreased by 78% for prelabour CSs, 52% for intrapartum CSs following spontaneous labour and 9% following labour induction. Adjusting for labour and delivery practices increased the unexplained variation in intrapartum CSs. The adjusted rates of severe maternal and neonatal morbidity were not significantly different across CS rate quintile groups, except for women in spontaneous labour, where the hospitals in the lowest CS quintile had the lowest neonatal morbidity rate. CONCLUSIONS: Differences in clinical practice were substantial contributors to variation in intrapartum CS rates. Our findings suggest that CS rates in some hospitals could be lowered without adversely affect pregnancy outcomes.
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Cesárea/estatística & dados numéricos , Parto Obstétrico/estatística & dados numéricos , Trabalho de Parto Induzido/estatística & dados numéricos , Complicações do Trabalho de Parto/epidemiologia , Adulto , Análise de Variância , Cesárea/tendências , Estudos de Coortes , Feminino , Humanos , Recém-Nascido , New South Wales/epidemiologia , Paridade , Gravidez , Resultado da GravidezRESUMO
BACKGROUND AND OBJECTIVES: To explore variation in red blood cell transfusion rates between hospitals, and the extent to which this can be explained. A secondary objective was to assess whether hospital transfusion rates are associated with maternal morbidity. MATERIALS AND METHODS: Linked hospital discharge and birth data were used to identify births (n = 279 145) in hospitals with at least 10 deliveries per annum between 2008 and 2010 in New South Wales, Australia. To investigate transfusion rates, a series of random-effects multilevel logistic regression models were fitted, progressively adjusting for maternal, obstetric and hospital factors. Correlations between hospital transfusion and maternal, neonatal morbidity and readmission rates were assessed. RESULTS: Overall, the transfusion rate was 1.4% (hospital range 0.6-2.9) across 89 hospitals. Adjusting for maternal casemix reduced the variation between hospitals by 26%. Adjustment for obstetric interventions further reduced variation by 8% and a further 39% after adjustment for hospital type (range 1.1-2.0%). At a hospital level, high transfusion rates were moderately correlated with maternal morbidity (0.59, P = 0.01), but not with low Apgar scores (0.39, P = 0.08), or readmission rates (0.18, P = 0.29). CONCLUSION: Both casemix and practice differences contributed to the variation in transfusion rates between hospitals. The relationship between outcomes and transfusion rates was variable; however, low transfusion rates were not associated with worse outcomes.
Assuntos
Unidade Hospitalar de Ginecologia e Obstetrícia/normas , Transfusão de Plaquetas/estatística & dados numéricos , Padrões de Prática Médica , Adulto , Austrália , Parto Obstétrico , Feminino , Humanos , Modelos Logísticos , New South Wales , Gravidez , Fatores de RiscoRESUMO
Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate.
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OBJECTIVES: To determine the most cost-effective strategy involving first-line treatment with long-acting risperidone, olanzapine, and quetiapine from the perspective of the Chinese health-care system. METHODS: A decision analytical model was applied. The model used a time horizon of 2 years. The probabilities of treatment response of different agents and the relapse and hospitalization rates were estimated by a Delphi panel of 17 senior psychiatrists in China. The unit cost for each medical service was calculated from the price system database built by China National Development and Reform Commission and the medical resource utilization was estimated by the Delphi panel. The principal efficacy measure was the proportion of patients successfully treated. Various sensitivity analyses were carried out to test the robustness of the model. RESULTS: The proportion of patients successfully treated over the 2-year period was 46.71% for long-acting risperidone, 39.93% for olanzapine, and 31.28% for quetiapine. The mean cost-effectiveness ratios were RMB189,427, RMB202,432, and RMB233,015 per successfully treated patient for long-acting risperidone, quetiapine and olanzapine, respectively. Results of the sensitivity analyses confirmed that the results were robust. CONCLUSIONS: The results showed that long-acting risperidone is more cost-effective than olanzapine and quetiapine for patients with schizophrenia in long-term maintenance treatment.
Assuntos
Antipsicóticos/economia , Benzodiazepinas/economia , Dibenzotiazepinas/economia , Risperidona/economia , Esquizofrenia/tratamento farmacológico , Esquizofrenia/economia , Antipsicóticos/administração & dosagem , Benzodiazepinas/uso terapêutico , China , Análise Custo-Benefício , Árvores de Decisões , Dibenzotiazepinas/uso terapêutico , Humanos , Injeções Intramusculares , Modelos Econômicos , Olanzapina , Fumarato de Quetiapina , Risperidona/administração & dosagemRESUMO
The mortality associated with primary and metastatic hepatic malignancies remains high because few patients are candidates for hepatic resection or transplantation. Resection is the most effective treatment for liver tumors but may be contraindicated by factors such as the tumor's location; hepatic transplantation can cure primary hepatocellular carcinoma and underlying cirrhosis, but a donor may not be immediately available. When resection or transplantation is not possible, thermal ablation is a reasonable therapeutic option. Effective destruction of tumors can be achieved with low recurrence rates and minimal complications or risk of death. In patients with primary hepatic malignancy, ablation treatment does not preclude subsequent transplantation. Although radiofrequency ablation is currently the most widely used thermal ablative technique for hepatic malignancy, microwave ablation is gaining popularity and eventually may prove to be more effective.
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Carcinoma Hepatocelular/terapia , Ablação por Cateter , Criocirurgia , Neoplasias Hepáticas/terapia , Micro-Ondas/uso terapêutico , Ablação por Cateter/métodos , Humanos , Neoplasias Hepáticas/secundário , Recidiva Local de Neoplasia , Seleção de Pacientes , Análise de SobrevidaRESUMO
Activation of cellular interferon-stimulated genes (ISGs) after infection with herpes simplex virus type 1 (HSV-1) or human cytomegalovirus (HCMV) was investigated. The level of ISG54-specific RNA in human fetal lung (HFL) or human foreskin (BJ) fibroblasts increased substantially after infection with either virus in the presence of cycloheximide. HSV-1 particles lacking glycoprotein D or glycoprotein H failed to induce ISG54-specific RNA synthesis, demonstrating that entry of virus particles rather than binding of virions to the cell surface was required for the effect. A DNA-binding complex that recognized an interferon-responsive sequence motif was induced upon infection with HSV-1 or HCMV in the presence of cycloheximide, and the complex was shown to contain the cell proteins interferon response factor 3 (IRF-3) and CREB-binding protein. IRF-3 was modified after infection with HSV-1 or HCMV to a form of lower electrophoretic mobility, consistent with phosphorylation. De novo transcription of viral or cellular genes was not required for the activation of IRF-3, since the effect was not sensitive to inhibition by actinomycin D. Infection of HFL fibroblasts with HSV-1 under conditions in which viral replication proceeded normally resulted in severely reduced levels of the IRF-3-containing complex, defining the activation of IRF-3 as a target for viral interference with ISG induction. In BJ fibroblasts, however, significant activation of IRF-3 was detected even when the viral gene expression program progressed to later stages, demonstrating that the degree of inhibition of the response was dependent on host cell type. As a consequence of IRF-3 activation, endogenous interferon was released from BJ cells and was capable of triggering the appropriate signal transduction pathway in both infected and uninfected cells. Activation of ISG54-specific RNA synthesis was not detected after infection of human U-373MG glioblastoma cells, showing that the induction of the response by infection is cell type dependent.
Assuntos
Infecções por Citomegalovirus/metabolismo , Citomegalovirus/fisiologia , Herpes Simples/metabolismo , Herpesvirus Humano 1/fisiologia , Fatores de Transcrição/metabolismo , Proteínas Reguladoras de Apoptose , Linhagem Celular , Humanos , Proteínas de Ligação a RNA , Replicação ViralRESUMO
The activation of gene expression by the human cytomegalovirus (HCMV) particle was investigated. The HCMV major immediate-early (IE) promoter was cloned upstream of the Escherichia coli lacZ coding sequences, and the resulting cassette was introduced into the genome of a herpes simplex virus type 1 (HSV-1) mutant lacking functional VP16. Upon infection with the HSV-1 recombinant in the presence of cycloheximide, to block de novo protein synthesis, expression of lacZ-specific transcripts was increased by fivefold when HCMV was included in the inoculum. Accumulation of HSV-1 IE RNAs was also stimulated by coinfection with HCMV, as was expression of the adenovirus 5 VAI transcript when the VAI gene was cloned into the HSV-1 genome. Coinfection with HCMV did not alter mRNA stability or uncoating of the HSV-1 genome. The coding sequences for the HCMV phosphoprotein pp71, controlled by the HCMV IE promoter, were cloned into an HSV-1 recombinant impaired for the production of the three major transactivators (VP16, ICP0, and ICP4) to yield a recombinant (in1324) which expressed pp71 but did not cause significant cytotoxicity. Infection with in1324 resulted in stimulation of HCMV IE, HSV-1 IE, and VAI expression, demonstrating that pp71 is responsible for the effects we observed when using the entire HCMV particle. Therefore, HCMV pp71 exhibits novel properties in its ability to stimulate gene expression from a range of promoters present in a herpesvirus genome.
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Citomegalovirus/genética , Regulação Viral da Expressão Gênica , Herpesvirus Humano 1/genética , Proteínas Virais/genética , Linhagem Celular , Genoma Viral , Humanos , Fosfoproteínas/genética , Plasmídeos , Regiões Promotoras GenéticasRESUMO
A 34-year-old woman became pregnant two years after having a simultaneous pancreas and kidney (SPK) transplantation, necessitated by type 1 diabetes and end-stage renal disease. The pregnancy was uneventful until 30 weeks' gestation, when she developed pancreatitis and a worsening of mild hypertension. A healthy 1700 g boy was delivered by caesarean section at 34 weeks' gestation. This is the first report of a successful pregnancy after SPK transplantation in Australia.
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Diabetes Mellitus Tipo 1/complicações , Nefropatias Diabéticas/cirurgia , Falência Renal Crônica/cirurgia , Transplante de Rim , Transplante de Pâncreas , Gravidez em Diabéticas , Adulto , Nefropatias Diabéticas/etiologia , Feminino , Humanos , Falência Renal Crônica/etiologia , Gravidez , Resultado da GravidezRESUMO
Herpes simplex virus type 1 (HSV-1) transcription can be arrested at the immediate early (IE) stage by continuous treatment of cells with inhibitors of protein synthesis, usually cycloheximide, from the time of infection. We have analysed the effect of cycloheximide on IE gene expression with HSV-1 mutants deficient in the production of functional levels of the three major transactivators, the virion protein (VP16) and two IE proteins (ICP0 and ICP4). Expression from the HSV-1 IE promoters that control synthesis of ICP0 and ICP27 was, unexpectedly, stimulated by inhibition of protein synthesis. The effect was observed for the ICP0 promoter in its normal genome location and also when cloned upstream of the Escherichia coli lacZ coding sequences and inserted into the viral thymidine kinase locus. Expression from the human cytomegalovirus major IE promoter, when cloned into the genome of HSV-1 mutants, was also increased by inhibition of protein synthesis. Cycloheximide did not affect the intracellular stability of lacZ-specific RNA, suggesting that the response represented an increase in mRNA production. Activation of the ICP0 promoter was observed when protein synthesis was blocked by alternative agents. Since inhibitors of protein synthesis are known to activate cellular signal transduction pathways, our findings demonstrate new mechanisms for the regulation of HSV-1 IE gene expression which may be important during latency and reactivation. The results also highlight previously unrecognized difficulties in analysing the intrinsic activities of promoters when cloned into the HSV-1 genome.
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Cicloeximida/farmacologia , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Herpesvirus Humano 1/genética , Inibidores da Síntese de Proteínas/farmacologia , Animais , Antígenos Virais/genética , Linhagem Celular , Cricetinae , Células HeLa , Proteína Vmw65 do Vírus do Herpes Simples/antagonistas & inibidores , Humanos , Proteínas Imediatamente Precoces/antagonistas & inibidores , Proteínas Imediatamente Precoces/biossíntese , Proteínas Imediatamente Precoces/genética , Regiões Promotoras Genéticas , RNA Viral/biossíntese , Ubiquitina-Proteína LigasesRESUMO
Herpes simplex virus type 1 (HSV-1) mutants defective in immediate-early (IE) gene expression do not readily enter productive replication after infection of tissue culture cells. Instead, their genomes are retained in a quiescent, nonreplicating state in which the production of viral gene products cannot be detected. To investigate the block to virus replication, we used the HSV-1 triple mutant in1820K, which, under appropriate conditions, is effectively devoid of the transactivators VP16 (a virion protein), ICP0, and ICP4 (both IE proteins). Promoters for the HSV-1 IE ICP0 gene or the human cytomegalovirus (HCMV) major IE gene, cloned upstream of the Escherichia coli lacZ coding sequences, were introduced into the in1820K genome. The regulation of these promoters and of the endogenous HSV-1 IE promoters was investigated upon conversion of the virus to a quiescent state. Within 24 h of infection, the ICP0 promoter became much less sensitive to transactivation by VP16 whereas the same element, when used to transform Vero cells, retained its responsiveness. The HCMV IE promoter, which is not activated by VP16, also became less sensitive to the HCMV functional homolog of VP16. Both elements remained available for transactivation by HSV-1 IE proteins at 24 h postinfection, showing that the in1820K genome was not irreversibly inactivated. The promoters controlling the HSV-1 ICP4, ICP22, and ICP27 genes also became essentially unresponsive to transactivation by VP16. The ICP0 promoter was induced when hexamethylene bisacetamide was added to cultures at the time of infection, but the response to this agent was also lost by 24 h after infection. Therefore, promoter elements within the HSV-1 genome are actively repressed in the absence of IE gene expression, and repression is not restricted specifically to HSV-1 IE promoters.
Assuntos
Citomegalovirus/genética , Regulação Viral da Expressão Gênica , Proteínas Imediatamente Precoces/biossíntese , Proteínas Imediatamente Precoces/genética , Regiões Promotoras Genéticas , Simplexvirus/genética , Simplexvirus/metabolismo , Animais , Linhagem Celular , Chlorocebus aethiops , Clonagem Molecular , Cricetinae , Cicloeximida/farmacologia , Citarabina/farmacologia , Citomegalovirus/fisiologia , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Humanos , Rim , Mutagênese , Proteínas Recombinantes de Fusão/biossíntese , Simplexvirus/fisiologia , Transfecção , Ubiquitina-Proteína Ligases , Células Vero , Vírion/efeitos dos fármacos , Vírion/fisiologia , beta-Galactosidase/biossínteseRESUMO
The concurrent problems of bleeding placenta praevia and thromboembolism present a difficult management problem. We present a case of pulmonary embolism successfully treated with low molecular weight heparin in a woman with a major grade placenta praevia, who required emergency operative delivery.
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Dalteparina/uso terapêutico , Placenta Prévia/complicações , Complicações Cardiovasculares na Gravidez/tratamento farmacológico , Embolia Pulmonar/tratamento farmacológico , Adulto , Cesárea , Feminino , Humanos , Masculino , Peso Molecular , Gravidez , Embolia Pulmonar/diagnóstico por imagem , UltrassonografiaRESUMO
The herpes simplex virus type 1 (HSV-1) mutant in 1814 contains an insertion mutation in the coding sequence for the virion transactivator protein VP16 and is thus impaired for the activation of immediate early (IE) gene expression. This virus was modified further by introducing the Moloney murine leukemia virus LTR promoter in place of the upstream sequences controlling expression of the IE regulatory protein ICPO, to yield mutant in 1820. In almost all cell types tested, in 1820 initiated infection less efficiently than in 1814, behaving as if lacking both VP16 and ICPO functions, but in BHK cells in 1820 was less impaired than in 1814. A rescuant of in 1820 at the VP16 locus, in 1825, also exhibited a host range phenotype, initiating replication as efficiently as wild-type HSV-1 in BHK cells but inefficiently in other cell types. In 1825 was unable to complement an ICPO null mutant in restricted cells, demonstrating that the promoter exchange prevented the expression of ICPO protein in functionally significant amounts. The novel host range properties of in 1820 provided a basis for the construction of additional viruses conditionally impaired for IE gene expression and assessment of their value as prototype vectors. Production of an HSV-1 mutant multiply defective in the expression of IE gene products was achieved by introduction of the temperature-sensitive mutation of HSV-1 tsK, which inactivates the IE transcription activator ICP4 at nonpermissive temperatures, into in 1820 to produce in 1820K. This mutant could be propagated effectively in BHK cells at 31 degrees but was effectively devoid of the major regulators ICPO, ICP4, and VP16 in other cells types at 38.5 degrees. Cultures could withstand infection with 5 PFU of in 1820K per cell without detectable cytopathology and could be reseeded to form colonies at approximately 90% efficiency. A derivative of in 1820K containing the Escherichia coli lacZ gene controlled by the human cytomegalovirus (HCMV) major IE promoter expressed low but detectable levels of beta-galactosidase in almost all cells after infection of cultures at 5 PFU per cell and incubation at 38.5 degrees. Cultures infected with 5 PFU per cell of an in 1820K derivative expressing neomycin phosphotransferase (npt) controlled by the HCMV IE promoter were resistant to killing by the antibiotic G418 for up to 3 days, and cell survival correlated with the retention of functional levels of npt. Mutants based on in 1820K can thus express foreign gene products in virtually all cells in a culture under conditions in which cytotoxicity is eliminated, demonstrating that progressive reduction of IE gene expression is an important step in the design of HSV-1-derived vectors.
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Regulação Viral da Expressão Gênica/genética , Genes Precoces , Herpesvirus Humano 1/genética , Proteínas Imediatamente Precoces/genética , Animais , Linhagem Celular , Sobrevivência Celular/genética , Chlorocebus aethiops , Cricetinae , Humanos , Mutagênese , Regiões Promotoras Genéticas , Ubiquitina-Proteína Ligases , Células VeroRESUMO
Pretreatment of tissue culture cells with alpha interferon (IFN-alpha) inhibits the transcription of herpes simplex virus type 1 (HSV-1) immediate-early (IE) genes, an effect which has been attributed to reduced transactivation of IE promoters by the virion protein VP16. Our previous demonstration that IFN-alpha inhibited the replication of the HSV-1 mutant in1814, which has a mutated VP16 unable to activate IE transcription, appeared to be incompatible with IFN-alpha having an effect on VP16 action (D. R. S. Jamieson, L. H. Robinson, J. I. Daksis, M. J. Nicholl, and C. M. Preston, J. Gen. Virol. 76:1417-1431, 1995). To investigate this observation further, cells were infected with a derivative of in1814 containing the lacZ gene controlled by the human cytomegalovirus IE promoter. The accumulation of HSV-1 IE RNA species was inhibited by IFN-alpha in these cells to the same extent as in cells infected with a virus rescued at the VP16 locus, and production of lacZ-specific RNA was also reduced, demonstrating that IFN-alpha can inhibit expression from a heterologous promoter that is not responsive to VP16. To provide a means of investigating the activity of VP16 on IE promoters not located in the HSV-1 genome, cell lines containing the neomycin phosphotransferase gene controlled by the HSV-1 IE ICPO promoter were constructed. Activation of the IE promoter by VP16 was not inhibited when the ICPO promoter was resident in the cell, demonstrating that VP16 function was unaffected by pretreatment of cells with IFN-alpha. The results suggest that IFN-alpha prevents the onset of IE transcription from the HSV-1 genome through a general mechanism rather than by having an effect specific to HSV-1 IE promoters.
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Genes Precoces , Proteína Vmw65 do Vírus do Herpes Simples/metabolismo , Herpesvirus Humano 1/metabolismo , Interferon-alfa/farmacologia , Transcrição Gênica/efeitos dos fármacos , Animais , Linhagem Celular , Chlorocebus aethiops , Cricetinae , Proteína Vmw65 do Vírus do Herpes Simples/biossíntese , Proteína Vmw65 do Vírus do Herpes Simples/genética , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 1/genética , Humanos , Proteínas Imediatamente Precoces/biossíntese , Rim , Pulmão , Mutagênese , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/biossíntese , Células Vero , beta-Galactosidase/biossínteseRESUMO
The development and utilization of a tissue culture system for the analysis of quiescent, nonreplicating herpes simplex virus type 1 (HSV-1) genomes is described. It was demonstrated previously that the HSV-1 Vmw65 mutant in1814, which is impaired for immediate early (IE) transcription, was retained for many days in human fetal lung (HFL) fibroblasts in a quiescent 'latent' state. Molecular analysis of the viral genome was not possible, however, due to residual expression of IE proteins and consequent cytotoxicity at high m.o.i. In the study reported here, IE transcription was reduced further by pretreatment of cells with interferon-alpha (IFN-alpha) and by the use of mutant in1820, a derivative of in1814 in which the Vmw110 promoter was replaced by the Moloney murine leukaemia virus (Momulv) enhancer. The Momulv enhancer was not expressed under IE conditions; thus in1820 was more impaired for replication than in1814 and behaved as if deficient for both Vmw65 and Vmw110. In cells pretreated with IFN-alpha and subsequently infected with in1820 cytotoxicity was overcome, enabling a tissue culture system to be developed in which all cells stably retained at least one quiescent viral genome. To assist the analysis of gene expression, in1820 was further modified by insertion of the Escherichia coli lacZ gene controlled by the human cytomegalovirus enhancer (mutant in1883) or the HSV-1 immediate early Vmw110 promoter (in1884). Expression of beta-galactosidase was not detected after infection of IFN-alpha-pretreated cells with in1883 or in1884 but could be induced in almost all cells containing a viral genome, by superinfection of cultures. In1820-derived viruses were retained for at least 9 days and were not reactivated by subculture of cells. A regular arrangement of nucleosomes, as found in cellular chromatin, was not detected on the viral genome at the thymidine kinase locus. The non-linear genome was a template for reactivation with no requirement for prior conversion to a linear form. A small number of remaining linear genomes resulted from incomplete uncoating of input virus.
Assuntos
DNA Viral/metabolismo , Expressão Gênica , Genoma Viral , Proteína Vmw65 do Vírus do Herpes Simples/biossíntese , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/metabolismo , Linhagem Celular , Elementos Facilitadores Genéticos , Feto , Fibroblastos , Expressão Gênica/efeitos dos fármacos , Genes Precoces/efeitos dos fármacos , Genótipo , Proteína Vmw65 do Vírus do Herpes Simples/genética , Herpesvirus Humano 1/crescimento & desenvolvimento , Humanos , Interferon-alfa/farmacologia , Cinética , Pulmão , Plasmídeos , Transcrição Gênica/efeitos dos fármacos , Transfecção , Ativação Viral , beta-Galactosidase/biossínteseRESUMO
Few obstetricians have much experience of the pregnant patient with a stoma. This paper was prompted by the management of 3 such patients in as many months and reviews the limited literature on stomas and pregnancy.