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Improvements in clinical assessment have occurred since the last published recommendations on the diagnosis and treatment of acute promyelocytic leukemia in 2013. Here, a committee of specialists of the Brazilian Association of Hematology, Hemotherapy and Cellular Therapy presents a comprehensive review on the current knowledge, focusing on the advances in diagnosis, risk assessment, and frontline and salvage therapy. The concept of urgent diagnosis is explored as well as the management of critical situations such as coagulopathy and differentiation syndrome. Recent adjustments in risk stratification based on white blood cell counts only are presented together with the incorporation of chemo-free regimens for non-high-risk patients. Special conditions such as acute promyelocytic leukemia in children, the elderly and pregnant women are discussed. Finally, acute promyelocytic leukemia is presented as a highly curable disease because of the real possibility of targeted therapy towards differentiation, and, paradoxically, as a serious and urgent condition that deserves prompt recognition and management to avoid early mortality.

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Cytokines are secretion proteins that mediate and regulate immunity and inflammation. They are crucial in the progress of acute inflammatory diseases and autoimmunity. In fact, the inhibition of proinflammatory cytokines has been widely tested in the treatment of rheumatoid arthritis (RA). Some of these inhibitors have been used in the treatment of COVID-19 patients to improve survival rates. However, controlling the extent of inflammation with cytokine inhibitors is still a challenge because these molecules are redundant and pleiotropic. Here we review a novel therapeutic approach based on the use of the HSP60-derived Altered Peptide Ligand (APL) designed for RA and repositioned for the treatment of COVID-19 patients with hyperinflammation. HSP60 is a molecular chaperone found in all cells. It is involved in a wide diversity of cellular events including protein folding and trafficking. HSP60 concentration increases during cellular stress, for example inflammation. This protein has a dual role in immunity. Some HSP60-derived soluble epitopes induce inflammation, while others are immunoregulatory. Our HSP60-derived APL decreases the concentration of cytokines and induces the increase of FOXP3+ regulatory T cells (Treg) in various experimental systems. Furthermore, it decreases several cytokines and soluble mediators that are raised in RA, as well as decreases the excessive inflammatory response induced by SARS-CoV-2. This approach can be extended to other inflammatory diseases.

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Collecting GPS data using mobile devices is essential to understanding human mobility. However, getting this type of data is tricky because of some specific features of mobile operating systems, the high-power consumption of mobile devices, and users' privacy concerns. Therefore, data of this kind are rarely publicly available for scientific purposes, while private companies that own the data are often reluctant to share it. Here we present a large anonymous longitudinal dataset of Activity Point Location (APL) generated from mobile devices' GPS tracking. The GPS data were collected by using the Google Location History (GLH), accessible in the Google Maps application. Our dataset, named AnLoCOV hereafter, includes anonymised data from 338 persons with corresponding socio-demographics over approximately ten years (2012-2022), thus covering pre- and post-COVID periods, and calculates over 2 million weekly-classified APL extracted from approximately 16 million GPS tracking points in Ecuador. Furthermore, we made our models publicly available to enable advanced analysis of human mobility and activity spaces based on the collected datasets.

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ABSTRACT Introduction: We performed cost-effectiveness and cost-utility analyses of the modified International Consortium on Acute Promyelocytic Leukemia protocol in Mexico for the treatment of acute promyelocytic leukemia Acute Promyelocytic Leukemia. Methods: We performed a three-state Markov analysis: stable disease (first line complete response [CR]), disease event (relapse, second line response and CR) and death. The modified IC-APL protocol is composed of three phases: induction, consolidation and maintenance. Cost and outcomes were used to calculate incremental cost-effectiveness ratios (ICERs); quality-adjusted life-years were used to calculate incremental cost-utility ratios (ICURs). Results: The CR was achieved in 18 patients (90%), treated with the IC-APL protocol as the first-line option; one patient (5%) died in induction, another one never achieved CR (5%); of the 18 patients that achieved CR, 1 relapsed (5.5%). The median treatment cost of the IC-APL protocol was $21,523 USD. The average life-year in our study was 7.8 years, while the average quality-adjusted life-year (QALY) was 6.1 years. When comparing the ICER between the IC-APL and the all-trans retinoic acid (ATRA) plus arsenic trioxide (ATO) protocols, we found the different costs of $6497, $19,133 and $17,123 USD in Italy, the USA and Canada, respectively. In relation to the ICUR, we found the different costs to be $13,955 and $11,979 USD in the USA and Canada, respectively. Conclusion: Taking into account the similar response rates, lower cost and easy access to the modified IC-APL regimen, we consider it a cost-effective and cost-utility protocol, deeming it the treatment of choice for our population.

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In approximately 15% of patients with acute myeloid leukemia (AML), total and phosphorylated EGFR proteins have been reported to be increased compared to healthy CD34+ samples. However, it is unclear if this subset of patients would benefit from EGFR signaling pharmacological inhibition. Pre-clinical studies on AML cells provided evidence on the pro-differentiation benefits of EGFR inhibitors when combined with ATRA or ATO in vitro. Despite the success of ATRA and ATO in the treatment of patients with acute promyelocytic leukemia (APL), therapy-associated resistance is observed in 5-10% of the cases, pointing to a clear need for new therapeutic strategies for those patients. In this context, the functional role of EGFR tyrosine-kinase inhibitors has never been evaluated in APL. Here, we investigated the EGFR pathway in primary samples along with functional in vitro and in vivo studies using several APL models. We observed that total and phosphorylated EGFR (Tyr992) was expressed in 28% and 19% of blast cells from APL patients, respectively, but not in healthy CD34+ samples. Interestingly, the expression of the EGF was lower in APL plasma samples than in healthy controls. The EGFR ligand AREG was detected in 29% of APL patients at diagnosis, but not in control samples. In vitro, treatment with the EGFR inhibitor gefitinib (ZD1839) reduced cell proliferation and survival of NB4 (ATRA-sensitive) and NB4-R2 (ATRA-resistant) cells. Moreover, the combination of gefitinib with ATRA and ATO promoted myeloid cell differentiation in ATRA- and ATO-resistant APL cells. In vivo, the combination of gefitinib and ATRA prolonged survival compared to gefitinib- or vehicle-treated leukemic mice in a syngeneic transplantation model, while the gain in survival did not reach statistical difference compared to treatment with ATRA alone. Our results suggest that gefitinib is a potential adjuvant agent that can mitigate ATRA and ATO resistance in APL cells. Therefore, our data indicate that repurposing FDA-approved tyrosine-kinase inhibitors could provide new perspectives into combination therapy to overcome drug resistance in APL patients.

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HnRNP K protein is a heterogeneous nuclear ribonucleoprotein which has been proposed to be involved in the leukemogenesis of acute promyelocytic leukemia (APL), as well as in differentiation induced by all-trans retinoic acid (ATRA). We previously demonstrated a connection between SET and hnRNP K function in head and neck squamous cell carcinoma (HNSCC) cells related to splicing processing. The objective of this study was to characterize the participation of hnRNP K and SET proteins in ATRA-induced differentiation in APL. We observed higher (5- to 40-fold) levels of hnRNP K and SET mRNA in APL patients at the diagnosis phase compared with induction and maintenance phases. hnRNP K knockdown using short-hairpin RNA led to cell death in ATRA-sensitive NB4 and resistant NB4-R2 cells by apoptosis with SET cleavage. In addition, hnRNP K knockdown increased granulocytic differentiation in APL cells, mainly in NB4-R2 with ATRA. hnRNP K knockdown had an effect similar to that of treatment with U0126 (an meiosis-specific serine/threonine protein kinase/ERK inhibitor), mainly in NB4-R2 cells. SET knockdown in APL cells revealed that apoptosis induction in cells with hnRNP K knockdown occurred by SET cleavage rather than by reduction in SET protein. Transplantation of NB4-R2 cells into nude mice confirmed that arsenic trioxide (ATO) combined with U0126 has higher potential against tumor progression when compared to ATO. Therefore, hnRNP K/SET and ERK are potential therapeutic targets for both antineoplastic leukemia therapy and relapsed APL patients with ATRA resistance.

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INTRODUCTION: We performed cost-effectiveness and cost-utility analyses of the modified International Consortium on Acute Promyelocytic Leukemia protocol in Mexico for the treatment of acute promyelocytic leukemia Acute Promyelocytic Leukemia. METHODS: We performed a three-state Markov analysis: stable disease (first line complete response [CR]), disease event (relapse, second line response and CR) and death. The modified IC-APL protocol is composed of three phases: induction, consolidation and maintenance. Cost and outcomes were used to calculate incremental cost-effectiveness ratios (ICERs); quality-adjusted life-years were used to calculate incremental cost-utility ratios (ICURs). RESULTS: The CR was achieved in 18 patients (90%), treated with the IC-APL protocol as the first-line option; one patient (5%) died in induction, another one never achieved CR (5%); of the 18 patients that achieved CR, 1 relapsed (5.5%). The median treatment cost of the IC-APL protocol was $21,523 USD. The average life-year in our study was 7.8 years, while the average quality-adjusted life-year (QALY) was 6.1 years. When comparing the ICER between the IC-APL and the all-trans retinoic acid (ATRA) plus arsenic trioxide (ATO) protocols, we found the different costs of $6497, $19,133 and $17,123 USD in Italy, the USA and Canada, respectively. In relation to the ICUR, we found the different costs to be $13,955 and $11,979 USD in the USA and Canada, respectively. CONCLUSION: Taking into account the similar response rates, lower cost and easy access to the modified IC-APL regimen, we consider it a cost-effective and cost-utility protocol, deeming it the treatment of choice for our population.

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Acute promyelocytic leukemia (APL), is now highly curable with treatment approaches that include all-trans retinoic acid (ATRA). The high incidence of APL in the Hispanics suggests an association with genetic variants in this population. Information on second primary malignancies (SPMs) in patients with APL is limited. The Surveillance, Epidemiology, and End Results (SEER) database was used to interrogate whether the rate of SPMs in patients with APL was associated with ethnicity and/or ATRA treatment. Between 2000 and 2016, 116 cases of SPM were diagnosed among 4019 patients with APL. The mean age at diagnosis of primary APL was 53.9 years (±15.7 years), and the mean age at diagnosis of SPMs was 59.0 years (±14.5 years). Comparisons with 3774 APL survivors who did not develop SPMs revealed that age ≥40 years at diagnosis of APL (p < 0.001) and non-Hispanic white ethnicity (p = 0.025) were associated with SPMs in APL survivors. Salivary gland, liver, and soft tissue malignancies were significantly more common in patients with primary APL than in individuals with non-APL malignancies. A risk analysis comparing patients who had APL with patients who had non-APL AML suggests that SPMs after APL is associated with ATRA treatment. Therefore, patient follow-up after APL should focus on early diagnosis of SPMs.

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The association of FLT3 mutations with white blood cell (WBC) counts at diagnosis and early death was studied in patients with acute promyelocytic leukemia (APL). Publications indexed in databases of biomedical literature were analyzed. Potential publication bias was evaluated by analyzing the standard error in funnel plots using the estimated relative risk (RR). Mixed-effect models were used to obtain the consolidated RR. All analyses were conducted using the R statistical software package. We used 24 publications in the final meta-analysis. Of 1005 males and 1376 females included in these 24 publications, 645 had FLT3-ITD (internal tandem duplication) mutations. Information on FLT3-D835 mutations was available in 10 publications for 175 patients. Concurrent occurrence of the two mutations was rare. WBC count at diagnosis was ≥10 × 109/L in 351 patients. For patients with the FLT3-ITD mutation, RR was 0.59 for overall survival (OS) and 1.62 for death during induction. For those with FLT3-D835 mutations, the RR was 0.50 for OS and 1.77 for death during induction. RR for WBC count ≥10 × 109/L was 3.29 and 1.48 for patients with FLT3-ITD and FLT3-D835, respectively. APL patients with FLT3-ITD or FLT3-D835 are more likely to present with elevated WBC counts and poorer prognosis than those without these mutations.

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OBJECTIVE: The clinical significance of anti-phosphatidylserine/prothrombin (aPS/PT) in antiphospholipid syndrome (APS) is still controversial. We assessed the prevalence of aPS/PT antibodies, their association with other anti-phospholipid antibodies (aPL) and with different APS clinical phenotypes. METHODS: We included 95 primary APS patients according to the Sydney classification criteria, and patients with thrombocytopenia and/or hemolytic anemia who also fulfilled the serological APS criteria. We tested aCL, anti-ß2GP-I and aPS/PT antibodies (both IgG and IgM isotypes) and lupus anticoagulant (LA). We used χ2 test, Spearman's correlation coefficient, Mann-Whitney U test and logistic regression. RESULTS: Seventy-seven percent of patients had thrombosis, 50% hematologic involvement and 25% obstetric events (non-exclusive groups). Twenty patients had only hematologic features. The prevalence of IgG and IgM aPS/PT antibodies was 61% and 60%, respectively. Patients with LA+ had a higher prevalence and higher titers of IgG and IgM aPS/PT antibodies. aPS/PT antibodies correlated with aPL antibodies including LA. IgG aPS/PT antibodies were associated with thrombosis (OR 8.6 [95% CI 2.13-33.8, p = 0.002]) and pure hematologic features (OR 0.2, CI 95% 0.05-0.97, p = 0.004). IgM anti-ß2GP-I antibodies conferred high risk for both hematologic (OR 7.9, 95% CI 1.88-34.61, p = 0.006) and thrombotic involvement (OR 7.4, 95% CI 1.76-31.12, p = 0.006). CONCLUSIONS: aPS/PT antibodies were highly prevalent and correlated with other aPL antibodies. IgG aPTS/PT conferred a high risk for thrombosis, but not for pure hematologic involvement. aPS/PT antibodies may be a useful serological tool in the diagnosis and phenotypic characterization of APS patients.

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Rheumatoid arthritis (RA) is a chronic T cell-mediated autoimmune disease. Serum autoantibodies against cyclic citrullinated peptides (anti-CCP) are significant markers for diagnosis and prognosis of this disease. Induction of immune tolerance as therapeutic approach for RA constitutes a current research focal point. In this sense, we carried out a phase I clinical trial in RA patients with a new therapeutic candidate (called CIGB-814); which induced mechanisms associated with restoration of peripheral tolerance in preclinical studies. CIGB 814 is an altered peptide ligand (APL), derived from a CD4+ T cell epitope of human heat-shock protein 60 (HSP60), an autoantigen involved in the pathogenesis of RA. Twenty patients with moderate disease activity were included in this open label trial. Sequential dose-escalation of 1, 2.5 and 5 mg of CIGB-814 was studied. Consecutive groups of six, five, and nine patients received a subcutaneous dose weekly of the peptide during the first month and one dose monthly during the next 5 months. The peptide was well tolerated and reduced disease activity. Here, we reported the quantification of anti-CCP antibodies during the treatment with this APL and in the follow-up stage. Anti-CCP antibodies were quantified in the plasma from patients by a commercial enzyme immunoassay at baseline (T0) and at weeks 28 and 48. Results showed that CIGB-814 induced a significant reduction of anti-CCP antibodies. In addition, this decrease correlated with clinical improvement in patients assessed by Disease Activity Score in 28 joints (DAS28) criteria. These findings reinforce the therapeutic potential of CIGB-814.

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CIGB-814, originally named as E18-3 APL1 or APL1 in preclinical experiments, is a novel therapeutic peptide candidate for Rheumatoid Arthritis (RA). It is an altered peptide ligand containing a novel CD4+ T-cell epitope of human heat shock protein 60 (83-109, MW 2988.38g/mol) with a mutation (D100→L) that increases its affinity for HLA-II type molecules associated to RA. A bioanalytical method, based on LC-MS/MS analysis, in the SRM mode was developed and fully validated to quantify this peptide in human plasma. An internal standard with the same amino acid sequence but labeled with three (13C615N2)-Lys residues was used for quantitation. The method provides a linear range from 1.5 to 48ng/mL (without matrix effect and carry over) and an accuracy and precision good enough for monitoring more than 80% of the AUC of the PK profile in a phase I clinical trial. The peptide was administered subcutaneously in three dose levels (1, 2.5 and 5mg) not normalized to the body weight of patients with RA. The low doses imposed an analytical challenge; however, a LLOQ of 1.5ng/mL enabled the PK analysis. The Cmax, reached at 0.5h, showed a great variability, that was most likely due to the non-normalized doses; the proposed mechanism for this peptide; and the variability between patients. A rapid clearance of this peptide (4-6h) is advantageous for an immunomodulatory drug, because the therapeutic schedule requires repeated dosages to restore peripheral tolerance.

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Induction of tolerance to autoantigens in vivo is a complex process that involves several mechanisms such as the induction of regulatory T cells and changes in the cytokine and chemokine profiles. This approach represents an attractive alternative for treatment of autoimmune diseases. APL-1 is an altered peptide ligand derived from a novel CD4 + T cell epitope of human heat-shock protein of 60 kDa (HSP60), an autoantigen involved in the pathogenesis of rheumatoid arthritis (RA). We have shown previously that this peptide efficiently inhibited the course of adjuvant-induced arthritis in Lewis rats and induced regulatory T cell (Treg) in ex vivo assay with PBMC isolated from RA patients. This study was undertaken to evaluate the therapeutic effect of APL-1 and its combination with methotrexate (MTX) in collagen-induced arthritis (CIA). CIA was induced in male DBA/1 mice at 8 weeks of age by immunization with chicken collagen. APL, MTX or both were administrated beginning from arthritis onset. Therapeutic effect was evaluated by arthritis and joint pathologic scores. In addition, TNFα and IL-10 in sera were measured by ELISA. Treg induction was assessed by FACS analysis. APL-1 inhibits efficiently the course of arthritis in CIA, similar to MTX. In addition, therapy with APL-1 plus MTX reduced CIA in mice, associated with an increase in Treg. These facts reinforce the therapeutic possibilities of APL-1 as a candidate drug for treatment of RA.

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ABSTRACT Acute promyelocytic leukemia has good prognosis in view of the high complete remission and survival rates achieved with therapies containing all-trans retinoic acid or arsenic trioxide. However, there is a significant risk of death during induction due to hemorrhage secondary to disseminated intravascular coagulation. This has contributed to a gap in the prognosis of patients between developed and developing countries. The International Consortium on Acute Promyelocytic Leukemia was created in 2005 and proposed a treatment protocol based on daunorubicin and all-trans retinoic acid stratified by risk geared toward developing countries. Herein are presented the results from the first patient cohort treated in a single developing country hospital employing a slightly modified version of the International Consortium protocol in a real life setting. Twenty patients with acute promyelocytic leukemia were enrolled: 27.8% had low-risk, 55.6% intermediate risk and 16.7% high-risk. The complete remission rate was 94.4% after a median of 42 days. Both relapse rates and death rates were one patient (5.5%) each. No deaths were observed during consolidation. After a median follow-up of 29 months, the overall survival rate was 89.1%. Efficacy and safety of the International Consortium on Acute Promyelocytic Leukemia protocol has been reproduced in acute promyelocytic leukemia patients from a developing country.

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Acute promyelocytic leukemia has good prognosis in view of the high complete remission and survival rates achieved with therapies containing all-trans retinoic acid or arsenic trioxide. However, there is a significant risk of death during induction due to hemorrhage secondary to disseminated intravascular coagulation. This has contributed to a gap in the prognosis of patients between developed and developing countries. The International Consortium on Acute Promyelocytic Leukemia was created in 2005 and proposed a treatment protocol based on daunorubicin and all-trans retinoic acid stratified by risk geared toward developing countries. Herein are presented the results from the first patient cohort treated in a single developing country hospital employing a slightly modified version of the International Consortium protocol in a real life setting. Twenty patients with acute promyelocytic leukemia were enrolled: 27.8% had low-risk, 55.6% intermediate risk and 16.7% high-risk. The complete remission rate was 94.4% after a median of 42 days. Both relapse rates and death rates were one patient (5.5%) each. No deaths were observed during consolidation. After a median follow-up of 29 months, the overall survival rate was 89.1%. Efficacy and safety of the International Consortium on Acute Promyelocytic Leukemia protocol has been reproduced in acute promyelocytic leukemia patients from a developing country.

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With the progressive aging of the Chilean population the diagnosis of neurodegenerative disorders is increasingly common, and among them is Primary Progressive Aphasia (PPA), with specific symptoms but late consultation. PPA is a clinical syndrome characterized by the degeneration of language regions in the dominant hemisphere that determines an insidious and progressive loss of language. Two types of PPA were recognized: Progressive non-fluent Aphasia (APnF) and Progressive Semantic Aphasia (DS), and was recently identified as a new type, Logopénica Progressive Aphasia (APL). We describe a case evaluated at the University of Chile Clinical Hospital of a woman of 54 years who have a history of 2-3 years of fluent speech with reduced speed due to the difficulty in finding words, had shortcomings in repetition of complex words, phrases and sentences, presence of phonemic paraphasias and impaired episodic memory. What in the phonological assessment supports a diagnosis of APL. Despite the above, the neurological examination was normal. The APL has been associated with Alzheimer's disease because it presents impaired episodic memory and the neuropathological changes most frequently encountered are amyloid plaques and neurofibrillary tangles. Through this article you may learn more about this disease and who to go if you or some colleague have symptoms to receive some guidance.

Con el progresivo envejecimiento de la población Chilena el diagnóstico de enfermedades neurodegenerativas es cada vez más com ún, y entre ellas está la afasia progresiva primaria (PPA), de síntomas específicos pero consulta tardía. PPA es un síndrome clínico caracterizado por la degeneración de las regiones del lenguaje en el hemisferio dominante que determina una pérdida insidiosa y progresiva del lenguaje. Fueron reconocidos dos tipos de PPA: Afasia Progresiva no fluente (APnF) y Afasia Progresiva Semántica (DS), y recientemente fue identificado un nuevo tipo como, Afasia Progresiva Logopénica (APL). Se describe un caso evaluado en el Hospital Clínico Universidad de Chile de una mujer de 54 años que presenta una historia de 2-3 años de habla fluida, con disminución de la velocidad debido a la dificultad para encontrar palabras, presentaba fallas en repetición de palabras complejas, frases y oraciones, presencia de parafasias fonémicas y problemas de memoria episódica. Lo que en la evaluación fonológica es compatible con un diagnóstico de APL. A pesar de todo lo anterior el examen neurológico fue normal. La APL se ha asociado con la enfermedad de Alzheimer, ya que presenta deterioro de la memoria episódica y los cambios neuropatológicos más frecuentes son las placas amiloides y los ovillos neurofibrilares. A través de este artículo podrán conocer más acerca de esta enfermedad y a quien acudir en caso de presentar síntomas usted o algún conocido para recibir alguna orientación.

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Este trabalho aborda o desenvolvimento local no município de Paraty, através da formação de APLs, especificamente neste caso voltados para a atividade turística. Através de informações obtidas por análise documental e entrevistas, pode-se analisar as potencialidades da região e apontar caminhos para incremento de sua competitividade, principalmente no que tange à integração e à formação de parcerias entre empresas, comunidade e poder público. Além disso, foram feitas sugestões para superar obstáculos, vencer desafios e aproveitar oportunidades, baseadas na vocação turística, para que a região se torne competitiva no mercado de destinos turísticos, fidelizando e ampliando a base de turistas, através do melhor aproveitamento de seus encantos naturais, históricos e culturais. Os principais resultados mostram que Paraty carece de melhorias de infraestrutura para desenvolver o turismo local, que vão desde o saneamento básico até o melhor treinamento e capacitação de mão de obra. Além disso, toda a estrutura existente ainda não pode ser considerada efetivamente um APL, apesar de já se observar uma organização da rede de pequenas e médias empresas voltada para o desenvolvimento turístico sustentável do município. O que se encontra, em termos de organização em rede, é um APL ainda informal, onde praticamente inexiste a liderança e a confiança interna.

This paper discusses the development in the municipality of Paraty, through the formation of LPAs, specifically in this case focused on tourism. By the information obtained through interviews and document analysis, we can analyze the region's potential and show ways to improve their competitiveness, especially regarding the integration and formation of partnerships between business, community and government. In addition, suggestions were made to overcome obstacles, overcome challenges and seize opportunities, based on tourist so that the region becomes competitive in the market of tourist destinations, customizing and expanding the base of tourists through the best use of their natural charms, history and culture. The main results show that Paraty lacks infrastructure improvements to develop local tourism, ranging from the basic sanitation to the best training and qualification of workforce. Moreover, the entire existing structure still can not be effectively considered an LPA, in spite of a network organization of small and medium enterprises focused on sustainable tourism development in the municipality. What becomes clear in terms of networking, is an informal LPA, where nonexistent leadership and inner confidence.

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Hybrid gene PML-RARα is the molecular target found in most cases of acute promyelocytic leukemia (APL) and has been used for diagnosis and minimal residual disease studies. The standard molecular technique employed is qualitative reverse transcriptase-polymerase chain reaction (RT-PCR), but with the emergence of real time PCR (Q-PCR), PML-RARα gene detection approaches have been described allowing transcript detection, with the methodological advantage of eliminating post-PCR processing. However, current protocols report the use of expensive fluorescent labeled probes, limiting its routine application in the laboratory. The objective of this study was to optimize PML-RARalpha gene detection method for Q-PCR, using SYBR® Green fluorescent dye. The analysis was performed with NB4 cellular lineage cDNA. Thermal cycling protocols, cDNA synthesis with random or specific primer and different MgCl2 and amplification primers concentrations were tested. Results show that amplification improved in the following conditions: 2 mM MgCl2, 10 pmol primers and cDNA synthesized with specific primer. There were no significant differences using annealing temperature (58ºC/30 s) followed by extension (72ºC/30 s) or annealing associated with extension as a single step (60ºC/45 s). This paper demonstrates the optimization of PML-RARα gene detection for Q-PCR studies using a technique considered sensitive and less expensive for routine use in the laboratory.

O gene híbrido PML-RARα é o marcador molecular presente na maioria dos casos de leucemia aguda promielocítica (LAP), sendo útil ao diagnóstico e ao estudo da doença residual mínima. A técnica molecular empregada como rotina laboratorial é a reação em cadeia da polimerase com transcrição reversa (RT-PCR) qualitativa, porém com o surgimento da PCR em tempo real (Q-PCR), foram descritas abordagens de detecção do gene PML-RARalfa possibilitando a quantificação de transcritos, com a vantagem metodológica da eliminação do processamento pós-PCR. No entanto, os protocolos relatam o uso de sondas fluorescentes de custo elevado para a rotina clínica, limitando sua aplicação. Este estudo teve como objetivo otimizar o método de detecção do gene PML-RARα para Q-PCR, utilizando como sistema de marcação fluorescente o intercalante SYBR® Green. A análise foi realizada com cDNA da linhagem celular NB4, tendo sido testados protocolos de termociclagem, síntese de cDNA com primer randômico ou específico e diferentes concentrações de MgCl2 e primers para amplificação. Os resultados mostraram amplificação mais eficiente nas seguintes condições: 2 mM MgCl2, 10 pmol de primers e cDNA sintetizado com primer específico. Não houve diferença na utilização de etapas para anelamento (58ºC/30 s) seguido de extensão (72ºC/30 s) ou etapa única de anelamento associado à extensão (60ºC/45 s). Esses resultados demonstram a otimização da detecção do gene PML-RARα para Q-PCR através de um método considerado sensível e de baixo custo para a rotina laboratorial.

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