Discovery of the Lanthipeptide Curvocidin†and Structural Insights into its Trifunctional Synthetase CuvL.

Lanthipeptides are ribosomally-synthesized natural products from bacteria featuring stable thioether-crosslinks and various bioactivities. Herein, we report on a new clade of tricyclic class-IV lanthipeptides with curvocidin from Thermomonospora curvata as its first representative. We obtained crystal structures of the corresponding lanthipeptide synthetase CuvL that showed a circular arrangement of its kinase, lyase and cyclase domains, forming a central reaction chamber for the iterative substrate processing involving nine catalytic steps. The combination of experimental data and artificial intelligence-based structural models identified the N-terminal subdomain of the kinase domain as the primary site of substrate recruitment. The ribosomal precursor peptide of curvocidin employs an amphipathic α-helix in its leader region as an anchor to CuvL, while its substrate core shuttles within the central reaction chamber. Our study thus reveals general principles of domain organization and substrate recruitment of class-IV and class-III lanthipeptide synthetases.

Mathematical modeling of plus-strand RNA virus replication to identify broad-spectrum antiviral treatment strategies.

Plus-strand RNA viruses are the largest group of viruses. Many are human pathogens that inflict a socio-economic burden. Interestingly, plus-strand RNA viruses share remarkable similarities in their replication. A hallmark of plus-strand RNA viruses is the remodeling of intracellular membranes to establish replication organelles (so-called "replication factories"), which provide a protected environment for the replicase complex, consisting of the viral genome and proteins necessary for viral RNA synthesis. In the current study, we investigate pan-viral similarities and virus-specific differences in the life cycle of this highly relevant group of viruses. We first measured the kinetics of viral RNA, viral protein, and infectious virus particle production of hepatitis C virus (HCV), dengue virus (DENV), and coxsackievirus B3 (CVB3) in the immuno-compromised Huh7 cell line and thus without perturbations by an intrinsic immune response. Based on these measurements, we developed a detailed mathematical model of the replication of HCV, DENV, and CVB3 and showed that only small virus-specific changes in the model were necessary to describe the in vitro dynamics of the different viruses. Our model correctly predicted virus-specific mechanisms such as host cell translation shut off and different kinetics of replication organelles. Further, our model suggests that the ability to suppress or shut down host cell mRNA translation may be a key factor for in vitro replication efficiency, which may determine acute self-limited or chronic infection. We further analyzed potential broad-spectrum antiviral treatment options in silico and found that targeting viral RNA translation, such as polyprotein cleavage and viral RNA synthesis, may be the most promising drug targets for all plus-strand RNA viruses. Moreover, we found that targeting only the formation of replicase complexes did not stop the in vitro viral replication early in infection, while inhibiting intracellular trafficking processes may even lead to amplified viral growth.

Mathematical modeling of plus-strand RNA virus replication to identify broad-spectrum antiviral treatment strategies.

Plus-strand RNA viruses are the largest group of viruses. Many are human pathogens that inflict a socio-economic burden. Interestingly, plus-strand RNA viruses share remarkable similarities in their replication. A hallmark of plus-strand RNA viruses is the remodeling of intracellular membranes to establish replication organelles (so-called "replication factories"), which provide a protected environment for the replicase complex, consisting of the viral genome and proteins necessary for viral RNA synthesis. In the current study, we investigate pan-viral similarities and virus-specific differences in the life cycle of this highly relevant group of viruses. We first measured the kinetics of viral RNA, viral protein, and infectious virus particle production of hepatitis C virus (HCV), dengue virus (DENV), and coxsackievirus B3 (CVB3) in the immuno-compromised Huh7 cell line and thus without perturbations by an intrinsic immune response. Based on these measurements, we developed a detailed mathematical model of the replication of HCV, DENV, and CVB3 and show that only small virus-specific changes in the model were necessary to describe the in vitro dynamics of the different viruses. Our model correctly predicted virus-specific mechanisms such as host cell translation shut off and different kinetics of replication organelles. Further, our model suggests that the ability to suppress or shut down host cell mRNA translation may be a key factor for in vitro replication efficiency which may determine acute self-limited or chronic infection. We further analyzed potential broad-spectrum antiviral treatment options in silico and found that targeting viral RNA translation, especially polyprotein cleavage, and viral RNA synthesis may be the most promising drug targets for all plus-strand RNA viruses. Moreover, we found that targeting only the formation of replicase complexes did not stop the viral replication in vitro early in infection, while inhibiting intracellular trafficking processes may even lead to amplified viral growth. Author summary: Plus-strand RNA viruses comprise a large group of related and medically relevant viruses. The current global pandemic of COVID-19 caused by the SARS-coronavirus-2 as well as the constant spread of diseases such as dengue and chikungunya fever show the necessity of a comprehensive and precise analysis of plus-strand RNA virus infections. Plus-strand RNA viruses share similarities in their life cycle. To understand their within-host replication strategies, we developed a mathematical model that studies pan-viral similarities and virus-specific differences of three plus-strand RNA viruses, namely hepatitis C, dengue, and coxsackievirus. By fitting our model to in vitro data, we found that only small virus-specific variations in the model were required to describe the dynamics of all three viruses. Furthermore, our model predicted that ribosomes involved in viral RNA translation seem to be a key player in plus-strand RNA replication efficiency, which may determine acute or chronic infection outcome. Furthermore, our in-silico drug treatment analysis suggests that targeting viral proteases involved in polyprotein cleavage, in combination with viral RNA replication, may represent promising drug targets with broad-spectrum antiviral activity.

One-Pot Chemoenzymatic Synthesis of Microviridin Analogs Containing Functional Tags.

Microviridins are a prominent family of ribosomally synthesized and posttranslationally modified peptides (RiPPs) featuring characteristic lactone and lactam rings. Their unusual cage-like architecture renders them highly potent serine protease inhibitors of which individual variants specifically inhibit different types of proteases of pharmacological interest. While posttranslational modifications are key for the stability and bioactivity of RiPPs, additional attractive properties can be introduced by functional tags. To date - although highly desirable - no method has been reported to incorporate functional tags in microviridin scaffolds or the overarching class of graspetides. In this study, a chemoenzymatic in vitro platform is used to introduce functional tags in various microviridin variants yielding biotinylated, dansylated or propargylated congeners. This straightforward approach paves the way for customized protease inhibitors with built-in functionalities that can help to unravel the still elusive ecological roles and targets of this remarkable class of compounds and to foster applications based on protease inhibition.

Self-Assembled Monolayer Epitope Bridges for Molecular Imprinting and Cancer Biomarker Sensing.

The research in biomedicine, cell signaling, diagnostics, and biocatalysis rely on selective protein binders that specifically capture a protein in a complex medium for either preparative or analytical use. These molecules are generally of biological origin and exposed to instability, denaturation, high cost, and inherently low binding capability. Imprinted polymers, serving as the artificial protein binders, demonstrate good potential to overcome these drawbacks. In this study, a novel epitope imprinting strategy is reported by employing double-cysteine-modified peptides as the templates and adsorbing the templates on a gold surface by means of forming self-assembled monolayer bridges, followed by electropolymerization to create a polymer network. The imprinted surface was initially designed to demonstrate specific affinity toward a short peptide (i.e., the epitope) or a target protein (i.e., neuron specific enolase) in buffer. This surface was subsequently used to measure the cancer biomarker in human serum that allows detecting 12 times lower concentration than threshold level of the biomarker. The molecular receptors exhibited a Kd < 65 pM for their respective target protein and low cross-reactivity with four nonspecific molecules. As compared to current strategies for the epitope imprinting, for example, through traditional, vertically adsorbed, or histidine-modified peptides, such a molecularly tunable system based on a surface-imprinting process may provide more efficient sensing systems with desirable affinity, sensitivity, and specificity in diagnostics applications.

Telomerase Does Not Improve DNA Repair in Mitochondria upon Stress but Increases MnSOD Protein under Serum-Free Conditions.

Telomerase is best known for its function in maintaining telomeres but has also multiple additional, non-canonical functions. One of these functions is the decrease of oxidative stress and DNA damage due to localisation of the telomerase protein TERT into mitochondria under oxidative stress. However, the exact molecular mechanisms behind these protective effects are still not well understood. We had shown previously that overexpression of human telomerase reverse transcriptase (hTERT) in human fibroblasts results in a decrease of mitochondrial DNA (mtDNA) damage after oxidative stress. MtDNA damage caused by oxidative stress is removed via the base excision repair (BER) pathway. Therefore we aimed to analyse whether telomerase is able to improve this pathway. We applied different types of DNA damaging agents such as irradiation, arsenite treatment (NaAsO2) and treatment with hydrogen peroxide (H2O2). Using a PCR-based assay to evaluate mtDNA damage, we demonstrate that overexpression of hTERT in MRC-5 fibroblasts protects mtDNA from H2O2 and NaAsO2 induced damage, compared with their isogenic telomerase-negative counterparts. However, overexpression of hTERT did not seem to increase repair of mtDNA after oxidative stress, but promoted increased levels of manganese superoxide dismutase (MnSOD) and forkhead-box-protein O3 (FoxO3a) proteins during incubation in serum free medium as well as under oxidative stress, while no differences were found in protein levels of catalase. Together, our results suggest that rather than interfering with mitochondrial DNA repair mechanisms, such as BER, telomerase seems to increase antioxidant defence mechanisms to prevent mtDNA damage and to increase cellular resistance to oxidative stress. However, the result has to be reproduced in additional cellular systems in order to generalise our findings.

Recognition of protein biomarkers using epitope-mediated molecularly imprinted films: Histidine or cysteine modified epitopes?

This research aims to engineer molecularly imprinted polymer (MIP)-based synthetic receptors for the molecular recognition of neuron specific enolase (NSE) biomarker. The synthetic peptide derived from the NSE was synthesized along with its cysteine and histidine modified versions. The modified peptides were utilized as templates for molecular imprinting, which was achieved by combination of epitope- and electrochemical surface imprinting strategy. The subsequently generated imprinted cavities were used for the detection of the NSE derived peptide and NSE. The imprints created with cysteine (CME) and histidine modified epitopes (HME) could detect the peptide in a concentration range of 2-128 µM and 15.6 nM to 128 µM, respectively. The recognition of NSE was achieved by the same imprints in a linear range of 1-64 ng mL-1 (CME) and 0.25-64 ng mL-1 (HME), respectively. The target molecules bound to the control polymer very weakly, confirming the high selectivity of the MIP cavities. Selectivity studies resulted in imprinting factors of 8.8 and 11 for the CME and HME imprints, respectively. The affinity analyses provided dissociation constants of 2.3 × 10-10 M and 3 × 10-11 M for NSE recognition using the corresponding epitope imprints. Cross-reactivity studies with non-specific molecules proved high specificity of the artificial receptors for the targets.

Prefrontal Cortex Corticotropin-Releasing Factor Receptor 1 Conveys Acute Stress-Induced Executive Dysfunction.

BACKGROUND: The medial prefrontal cortex (mPFC) subserves complex cognition and is impaired by stress. Corticotropin-releasing factor (CRF), through CRF receptor 1 (CRFR1), constitutes a key element of the stress response. However, its contribution to the effects of stress in the mPFC remains unclear. METHODS: Mice were exposed to acute social defeat stress and subsequently to either the temporal order memory (n = 11-12) or reversal learning (n = 9-11) behavioral test. Changes in mPFC Crhr1 messenger RNA levels were measured in acutely stressed mice (n = 12). Crhr1loxP/loxP mice received either intra-mPFC adeno-associated virus-Cre or empty microinjections (n = 17-20) and then were submitted to acute stress and later to the behavioral tests. Co-immunoprecipitation was used to detect activation of the protein kinase A (PKA) signaling pathway in the mPFC of acutely stressed mice (n = 8) or intra-mPFC CRF injected mice (n = 7). Finally, mice received intra-mPFC CRF (n = 11) and/or Rp-isomer cyclic adenosine 3',5' monophosphorothioate (Rp-cAMPS) (n = 12) microinjections and underwent behavioral testing. RESULTS: We report acute stress-induced effects on mPFC-mediated cognition, identify CRF-CRFR1-containing microcircuits within the mPFC, and demonstrate stress-induced changes in Crhr1 messenger RNA expression. Importantly, intra-mPFC CRFR1 deletion abolishes acute stress-induced executive dysfunction, whereas intra-mPFC CRF mimics acute stress-induced mPFC dysfunction. Acute stress and intra-mPFC CRF activate the PKA signaling pathway in the mPFC, leading to cyclic AMP response element binding protein phosphorylation in intra-mPFC CRFR1-expressing neurons. Finally, PKA blockade reverses the intra-mPFC CRF-induced executive dysfunction. CONCLUSIONS: Taken together, these results unravel a molecular mechanism linking acute stress to executive dysfunction via CRFR1. This will aid in the development of novel therapeutic targets for stress-induced cognitive dysfunction.

DNA methylation transcriptionally regulates the putative tumor cell growth suppressor ZNF677 in non-small cell lung cancers.

In our study, we investigated the role of ZNF677 in non-small cell lung cancers (NSCLC). By comparing ZNF677 expression in primary tumor (TU) and in the majority of cases also of corresponding non-malignant lung tissue (NL) samples from > 1,000 NSCLC patients, we found tumor-specific downregulation of ZNF677 expression (adjusted p-values < 0.001). We identified methylation as main mechanism for ZNF677 downregulation in NSCLC cells and we observed tumor-specific ZNF677 methylation in NSCLC patients (p < 0.0001). In the majority of TUs, ZNF677 methylation was associated with loss of ZNF677 expression. Moreover, ZNF677 overexpression in NSCLC cells was associated with reduced cell proliferation and cell migration. ZNF677 was identified to regulate expression of many genes mainly involved in growth hormone regulation and interferon signalling. Finally, patients with ZNF677 methylated TUs had a shorter overall survival compared to patients with ZNF677 not methylated TUs (p = 0.013). Overall, our results demonstrate that ZNF677 is trancriptionally regulated by methylation in NSCLCs, suggest that ZNF677 has tumor cell growth suppressing properties in NSCLCs and that ZNF677 methylation might serve as prognostic parameter in these patients.

Persistence of HCV in quiescent hepatic cells under conditions of an interferon-induced antiviral response.

BACKGROUND & AIMS: Hepatitis C virus (HCV) is a common cause of chronic liver disease. Many patients do not clear the viral infection; little is known about the mechanisms of HCV persistence or the frequent failure of interferon (IFN) to eliminate it. Better culture systems are needed to study viral replication in quiescent liver cells. METHODS: We used human hepatoma (Huh7.5) cells and those that had undergone proliferation arrest and differentiation (Huh7.5(dif)) to study the persistence of HCV infection following exposure of the cells to IFN-α and to compare the antiviral effects of IFN-α and IFN-λ. We validated these results with primary human hepatocytes and Huh7 cells that expressed an IFN-inducible fluorophore. RESULTS: Following infection of Huh7.5(dif) cells, HCV replicated persistently and released infectious particles. Long-term exposure of the cells to IFN-α reduced HCV replication ∼1000-fold but did not eliminate the virus; viral replication rebounded after withdrawal of IFN, as it does in patients with chronic HCV infection. HCV replicated at higher levels, but not exclusively, in cells that had a low level of response to IFN-α. Following incubation of cells with equipotent concentrations of IFN-α or IFN-λ, Huh7.5(dif) cells expressed a wider pattern of IFN-stimulated genes than undifferentiated Huh7.5 cells or primary human hepatocytes, indicating that the antiviral response depends on the differentiation status of the cells. CONCLUSIONS: We developed a cell culture system using hepatoma cells to study persistent HCV infection during the type I or type III IFN-induced antiviral response. The level and range of the antiviral responses were associated with the differentiation status of the cells. We propose that HCV exploits the stochastic nature of the response of hepatocytes to IFN to sustain persistence.

Estimação de sub-registro de nascidos vivos pelo método de captura e recaptura, Sergipe / Estimation of live birth underreporting with a capture-recapture method, Sergipe, Northeastern Brazil / Estimación de subregistro de nacidos vivos por el método de captura-recaptura, Sergipe, Noreste de Brasil, 2006

OBJETIVO: Estimar o número de ocorrências de nascidos vivos e, por conseqüência, o sub-registro civil de nascidos vivos. MÉTODOS: As bases de dados do Sistema Nacional de Informação sobre Nascidos Vivos e do Registro Civil do Instituto Brasileiro de Geografia e Estatística, nos segundo e terceiro trimestres de 2006 do estado de Sergipe, foram pareadas por relacionamento determinístico a partir do número da Declaração de Nascido Vivo. A desagregação geográfica adotada foi a de microrregião de residência da mãe. Os modelos de Huggins para populações fechadas foram aplicados para estimar as probabilidades de captura em cada base e o total de nascidos vivos ocorrido no período, dentro de cada desagregação geográfica. O aplicativo utilizado para as estimações foi o Software MARK®. RESULTADOS: O sub-registro civil no período analisado foi de 19,3 por cento. A aplicação do método de captura-recaptura para estimar sub-registro de nascidos vivos é factível, inclusive para desagregações geográficas menores do que unidade da federação. O relacionamento determinístico foi prejudicado em quatro microrregiões, devido à falta de preenchimento do número da Declaração de Nascido Vivo na base do Instituto Brasileiro de Geografia e Estatística. Identificou-se que a idade da mãe afeta a probabilidade de captura pelo Registro Civil, característica de heterogeneidade na população de nascidos vivos. CONCLUSÕES: O método de captura-recaptura mostrou-se viável para a estimação de sub-registro de nascidos vivos.

OBJECTIVE: Estimate the number of live births and, therefore, underreporting of live births. METHODS: The databases of the Live Birth Information System and the Civil Registry of the Brazilian Institute of Geography and Statistics, from the second and third trimesters of 2006 in Sergipe state (Northeastern Brazil) were paired by deterministic linkage based on the number of the Live Birth Declaration. The geographic disaggregation utilized was mother's microregion of residence. Huggins closed population models were used to estimate the capture probabilities for each database and the total live births during the period, within each geographic subdivision. MARK® software was used for the estimates. RESULTS: Underregistration during the period studied was 19.3 percent. Application of the capture-recapture method to estimate underregistration of live births is possible, including for geographic disaggregations smaller than a state. The deterministic linkage was impaired in four microregions, due to non-inclusion of the Live Birth Declaration number in the database of the Brazilian Institute of Geography and Statistics. Maternal age, a heterogeneity characteristic in the population of live births, affected the probability of capture by the civil registry. CONCLUSIONS: Capture-recapture was a viable method to estimate the underregistration of live births.

OBJETIVO: Estimar el número de ocurrencias de nacidos vivos, y en consecuencia, el subregistro civil de nacidos vivos. MÉTODOS: Las bases de datos del Sistema Nacional de Información sobre Nacidos Vivos y del Registro Civil del Instituto Brasileño de Geografía y Estadística, en los segundo y tercero trimestres de 2006 del estado de Sergipe (Noreste de Brasil), fueron pareadas por relación determinística a partir del número de la Declaración de Nacido Vivo. La desagregación geográfica adoptada fue la de microregión de residencia de la madre. Los modelos de Huggins para poblaciones cerradas fueron aplicados para estimar las probabilidades de captura en cada base y el total de nacidos vivos ocurrido en el período, dentro de cada desagregación geográfica. El aplicativo utilizado para las estimaciones fue el Software MARK®. RESULTADOS: El subregistro civil en el período analizado fue de 19,3 por ciento. La aplicación del método de captura-recaptura para estimar subregistro de nacidos vivos es factible, inclusive para desagregaciones geográficas menores que la unidad de federación. La relación deterministica fue perjudicada en cuatro microregiones, debido a la falta de llenado del número de la Declaración de Nacido Vivo en la base del Instituto Brasileño de Geografía y Estadística. Se identificó que la edad de la madre afecta la probabilidad de captura por el Registro Civil, característica de heterogeneidad en la población de nacidos vivos. CONCLUSIONES: El método de captura-recaptura se mostró viable para la estimación de subregistro de nacidos vivos.

Automedicação em adultos de baixa renda no município de São Paulo / Automedicación en adultos de baja renta en el municipio de Sao Paulo / Self-medication in low-income adults in Southeastern Brazil

OBJETIVO: Estimar a proporção de automedicação em adultos de baixa renda e identificar fatores associados. MÉTODOS: Foram utilizados dados de inquérito populacional realizado no município de São Paulo em 2005, cujo plano amostral incluiu dois domínios, favela e não favela, com amostragem por conglomerados em dois estágios, totalizando 3.226 indivíduos elegíveis. Além de características sociodemográficas e econômicas, foram analisados: uso de medicamentos nos 15 dias anteriores à entrevista, tipo de acesso (gratuito, comprado ou outra) aos medicamentos e os tipos de morbidades (crônicas ou agudas) tratadas, em análise de regressão logística múltipla. RESULTADOS: A proporção de automedicação foi de 27 por cento a 32 por cento. Automedicação esteve fortemente associada à morbidade aguda, ao acesso ao medicamento por compra, à idade menor que 47 anos e medicamentos do grupo terapêutico que atuam no sistema nervoso central. O grupo que atua no sistema nervoso central foi o mais utilizado na automedicação. CONCLUSÕES: O acesso gratuito aos medicamentos mostrou-se fator de proteção para a automedicação. A distribuição de medicamentos e o atendimento adequado devem ser considerados para orientação e redução dos riscos que o uso irracional de medicamentos pode gerar à saúde.

OBJETIVO: Estimar la proporción da automedicación en adultos de baja renta e identificar factores asociados. MÉTODOS: Se utilizaron datos de pesquisa poblacional realizado en el municipio de Sao Paulo, Sureste de Brasil, en 2005, cuyo plan de muestreo incluyó dos dominios, barrio y no barrio, con muestreo por conglomerados en dos fases, totalizando 3.226 individuos elegibles. Además de las características sociodemográficas y económicas, se analizaron: uso de medicamentos en los 15 días anteriores a la entrevista, tipo de acceso (gratuito, comprado u otra) a los medicamentos y los tipos de morbilidades (crónicas o agudas) tratadas, en análisis de regresión logística múltiple. RESULTADOS: La proporción de automedicación fue de 27% a 32%. La automedicación estuvo fuertemente asociada a la morbilidad aguda, al acceso al medicamento por compra, a la edad menor de 47 años y medicamentos del grupo terapéutico que actúan en el sistema nervioso central. El grupo que actúa en el sistema nervioso central fue el más utilizado en la automedicación. CONCLUSIONES: El acceso gratuito a los medicamentos se mostró como factor de protección para la automedicación. La distribución de medicamentos y la atención adecuada deben ser considerados para orientación y reducción de los riesgos que el uso irracional de medicamentos puede generar para la salud.

Estimação de sub-registro de nascidos vivos pelo método de captura e recaptura / Estimation of underreporting of live births by the capture-recapture

Introdução - O método de captura-recaptura vem sendo empregado em Epidemiologia desde meados do século XX, e se consolidou a partir dos anos 1990, quando se nota grande número de publicações sobre sua aplicação e desenvolvimento nesta área. O sub-registro de eventos vitais ainda se revela um entrave para o cálculo direto de indicadores como os de fecundidade e mortalidade infantil, forçando seu cálculo indireto através de métodos demográficos, cujos procedimentos não permitem estimação em níveis geográficos menores do que unidade da federação, em períodos intercensitários. Objetivo Estimar o sub-registro de nascidos vivos, aplicando o método de captura-recaptura para populações fechadas. Métodos - As bases de dados do Sistema Nacional de Informação sobre Nascidos Vivos (SINASC) e do Registro Civil do IBGE, nos segundo e terceiro trimestres de 2006 do estado de Sergipe, foram pareadas por relacionamento determinístico a partir do número da Declaração de Nascido Vivo. As desagregações geográficas adotadas foram as de microrregião e regional de saúde de residência da mãe. Os modelos de Huggins para populações fechadas foram aplicados para estimar as probabilidades de captura em cada uma das bases e o total de nascidos vivos ocorrido no período, dentro de cada desagregação geográfica O aplicativo utilizado para as estimações foi o Software MARK®. Resultados A aplicação do método de captura e recaptura para estimar sub-registro de nascidos vivos é factível, inclusive para desagregações geográficas menores do que unidade da federação. O relacionamento determinístico foi prejudicado em quatro microrregiões e em uma regional de saúde, devido à falta de preeenchimento do número da Declaração de Nascido Vivo na base do IBGE. O aplicativo MARK® apresenta interface amigável, o que facilitou a construção e seleção dos modelos estatísticos, permitindo identificar que a idade da mãe afeta a probabilidade de captura pelo Registro Civil, característica de heterogeneidade na p...

PUVA x catarata: revisão sistemática da literatura / PUVA x cataracts: systematic review of the literature

A fim de se encontrar as evidências sobre a ocorrência de catarata em pacientes submetidos à PUVA terapia, realizou-se revisão sistemática da literatura publicada, utilizando-se as bases de dados Medline, Lilacs, Cochrane Library, Excerpta Medica e o programs MICROMEDEX. Foram elaboradas estratégias de busca para cada base de dados. Após aplicação dos critérios de seleção definidos, incluíram-se 30 artigos que representavam 21 estudos que abordavam o tema. Os dados de cada estudo foram recolhidos a partir de um formulário de coleta criado para este fim. A avaliação da qualidade dos estudos se deu por classificação das evidências em categorias e posterior relação destas categorias com a força de recomendação das evidências para a prática clínica, de acordo com critérios previamente publicados. Ainda, elaborou-se um esquema de classificação de qualidade específico para os estudos incluídos. Realizou-se análise estatística dos dados apresentados através de análise de sobrevida, utilizando-se o modelo de Cox de hazards proporcionais. As evidências publicadas das bases de dados, capturadas pelas estratégias de busca e selecionadas pelos critérios de inclusão e exclusão não são suficientes para se afirmar se a catarata pode ou não ser uma reação adversa à PUVA terapia. Não foi possível, também, encontrar um modelo matemático que pudesse indicar relação entre as variáveis explicativas e a função de hazards.