A Review of EPDM (Ethylene Propylene Diene Monomer) Rubber-Based Nanocomposites: Properties and Progress.

Ethylene propylene diene monomer (EPDM) is a synthetic rubber widely used in industry and commerce due to its high thermal and chemical resistance. Nanotechnology has enabled the incorporation of nanomaterials into polymeric matrixes that maintain their flexibility and conformation, allowing them to achieve properties previously unattainable, such as improved tensile and chemical resistance. In this work, we summarize the influence of different nanostructures on the mechanical, thermal, and electrical properties of EPDM-based materials to keep up with current research and support future research into synthetic rubber nanocomposites.

Sustainable Composites: Analysis of Filler-Rubber Interaction in Natural Rubber-Styrene-Butadiene Rubber/Polyurethane Composites Using the Lorenz-Park Method and Scanning Electron Microscopy.

This study examined micronized polyurethane residues as a reinforcing filler in elastomeric composites made from natural rubber (NR) and styrene-butadiene rubber (SBR). Due to growing environmental concerns, this research aimed to find sustainable alternatives to synthetic materials. The results indicated that adding micronized polyurethane improved the mechanical properties of the composites, reinforcing the polymer matrix and increasing the cross-link density as a barrier against solvents. The composites met the requirements for industrial applications, though; at 40 phr of polyurethane filler, material deformation was reduced, indicating saturation. FTIR analysis confirmed the homogeneity of the materials without chemical reactions, while electron microscopy revealed an increase in the number of particles and irregularities with the filler. The composite with 10 phr showed a lower volume loss in abrasion resistance, meeting the standards for soles. The composite with 30 phr of polyurethane achieved the best results without the filler's saturation and met the footwear industry's requirements. The results show the potential for sustainable practices in industry using this elastomeric blend.

Early outcomes of transcatheter tricuspid valve-in-valve implantation: a case series.

OBJECTIVES: In this study, we sought to evaluate early outcomes of transcatheter valve-in-valve implantation in patients with a degenerated bioprosthesis in the tricuspid position. METHODS: We used a prospective study, which included patients with a degenerated bioprosthesis in the tricuspid position who were considered high-risk by our heart team and who underwent a valve-in-valve implantation. The procedures were performed via transjugular venous access and were done with the patient under general anaesthesia with transoesophageal echocardiographic and fluoroscopic guidance. Perioperative data were analysed, and the patients were followed prospectively. RESULTS: Seven patients were included. The baseline diagnoses were 3 patients with Ebstein's anomaly, 1 patient with tetralogy of Fallot, 1 patient with neonatal endocarditis, 1 patient with ventricular septal defect with a double tricuspid lesion and 1 patient with rheumatic mitral and tricuspid valve who underwent a combined transapical mitral and transjugular tricuspid valve-in-valve implantation. The mean age was 33 ± 10.8 years and 57.1% of the patients were men. The mean number of previous thoracotomies was 3 ± 2 (range 1-5) procedures. The mean follow-up was 1.24 years. The implant was successful in all cases, and there was no need for conversion to open surgery. There were no deaths during the study period, and all patients are currently in the New York Heart Association functional class I/II. There was a statistically significant difference when the mean transvalvular gradients preimplantation and postimplantation were compared (P < 0.001). CONCLUSIONS: Percutaneous tricuspid valve implantation should be considered a safe and effective therapy and stands as a viable, reliable alternative for the treatment of a degenerated bioprosthesis in high-surgical-risk/inoperable patients.

Thrombocytopenia After Transcatheter Valve-in-Valve Implantation: Prognostic Marker or Mere Finding?

OBJECTIVE: To analyze the behavior of platelets after transcatheter valve-in-valve implantation for the treatment of degenerated bioprosthesis and how they correlate with adverse events upon follow-up. METHODS: Retrospective analysis of 28 patients who received a valve-in-valve implant, 5 in aortic, 18 in mitral and 5 in tricuspid positions. Data were compared with 74 patients submitted to conventional redo valvular replacements during the same period, and both groups' platelet curves were analyzed. Statistical analysis was conducted using the IBM SPSS Statistics(r) 20 for Windows. RESULTS: All patients in the valve-in-valve group developed thrombocytopenia, 25% presenting mild (<150.000/µL), 54% moderate (<100.000/µL) and 21% severe (<50.000/µL) thrombocytopenia. The platelet nadir was on the 4th postoperative day for aortic ViV, 2nd for mitral and 3rd for tricuspid patients, with the majority of patients recovering regular platelet count. However, the aortic subgroup comparison between valve-in-valve and conventional surgery showed a statistically significant difference from the 7th day onwards, where valve-in-valve patients had more severe and longer lasting thrombocytopenia. This, however, did not translate into a higher postoperative risk. In our study population, postoperative thrombocytopenia did not correlate with greater occurrence of adverse outcomes and only normal preoperative platelet count could significantly predict a postoperative drop >50%. CONCLUSION: Although thrombocytopenia is an extremely common finding after valve-in-valve procedures, the degree of platelet count drop did not correlate with greater incidence of postoperative adverse outcomes in our study population.

Thrombocytopenia after transcatheter valve-in-valve implantation: prognostic marker or mere finding?

Abstract Objective: To analyze the behavior of platelets after transcatheter valve-in-valve implantation for the treatment of degenerated bioprosthesis and how they correlate with adverse events upon follow-up. Methods: Retrospective analysis of 28 patients who received a valve-in-valve implant, 5 in aortic, 18 in mitral and 5 in tricuspid positions. Data were compared with 74 patients submitted to conventional redo valvular replacements during the same period, and both groups' platelet curves were analyzed. Statistical analysis was conducted using the IBM SPSS Statistics(r) 20 for Windows. Results: All patients in the valve-in-valve group developed thrombocytopenia, 25% presenting mild (<150.000/µL), 54% moderate (<100.000/µL) and 21% severe (<50.000/µL) thrombocytopenia. The platelet nadir was on the 4th postoperative day for aortic ViV, 2nd for mitral and 3rd for tricuspid patients, with the majority of patients recovering regular platelet count. However, the aortic subgroup comparison between valve-in-valve and conventional surgery showed a statistically significant difference from the 7th day onwards, where valve-in-valve patients had more severe and longer lasting thrombocytopenia. This, however, did not translate into a higher postoperative risk. In our study population, postoperative thrombocytopenia did not correlate with greater occurrence of adverse outcomes and only normal preoperative platelet count could significantly predict a postoperative drop >50%. Conclusion: Although thrombocytopenia is an extremely common finding after valve-in-valve procedures, the degree of platelet count drop did not correlate with greater incidence of postoperative adverse outcomes in our study population.

A New Experimental Device for Transapical Access of the Aortic and Mitral Valves as well as the Aorta in its Various Segments.

OBJECTIVE:: To present the results of a new experimental device developed to facilitate the transapical access in endovascular treatment of structural heart diseases. It aims to reduce the risk of bleeding and complications in this type of access and demonstrate the device as a safe, fast and effective alternative. METHODS:: CorPoint is composed of three parts: introducer, base with coiled spring, and closing capsule. By rotating movements, the spring is introduced into the myocardium and progressively approaches the base to the surface of the heart. Guidewires and catheters are inserted through the hollow central part and, at the end of the procedure, the capsule is screwed over the base, therefore stopping any bleeding. RESULTS:: The device was implanted in 15 pigs, weighing 60 kg each, through an anterolateral thoracotomy, while catheters were introduced and guided by fluoroscopy. All animals had minimal bleeding; introducers with diameter up to 22 Fr were used and various catheters and guidewires were easily handled. After finishing the procedure, the closing capsule was attached and no bleeding was observed at the site. CONCLUSION:: This new device has proved effective, fast and secure for the transapical access. This shows great potential for use, especially by ensuring an easier and direct access to the mitral and aortic valves; the shortest distance to be traveled by catheters; access to the ascending and descending aorta; decreased bleeding complications; decreased surgical time; and the possibility of allowing the technique to evolve and become totally percutaneous.

A new experimental device for transapical access of the aortic and mitral valves as well as the aorta in its various segments

Abstract Objective: To present the results of a new experimental device developed to facilitate the transapical access in endovascular treatment of structural heart diseases. It aims to reduce the risk of bleeding and complications in this type of access and demonstrate the device as a safe, fast and effective alternative. Methods: CorPoint is composed of three parts: introducer, base with coiled spring, and closing capsule. By rotating movements, the spring is introduced into the myocardium and progressively approaches the base to the surface of the heart. Guidewires and catheters are inserted through the hollow central part and, at the end of the procedure, the capsule is screwed over the base, therefore stopping any bleeding. Results: The device was implanted in 15 pigs, weighing 60 kg each, through an anterolateral thoracotomy, while catheters were introduced and guided by fluoroscopy. All animals had minimal bleeding; introducers with diameter up to 22 Fr were used and various catheters and guidewires were easily handled. After finishing the procedure, the closing capsule was attached and no bleeding was observed at the site. Conclusion: This new device has proved effective, fast and secure for the transapical access. This shows great potential for use, especially by ensuring an easier and direct access to the mitral and aortic valves; the shortest distance to be traveled by catheters; access to the ascending and descending aorta; decreased bleeding complications; decreased surgical time; and the possibility of allowing the technique to evolve and become totally percutaneous.

Homocysteine and other markers of cardiovascular risk during a manic episode in patients with bipolar disorder.

OBJECTIVE: To evaluate serum levels of different biomarkers associated with cardiovascular disease in patients with bipolar disorder (BD). Patients were prospectively evaluated in two separate instances: during acute mania and after remission of manic symptoms. All measurements were compared with those of healthy controls. METHODS: The study included 30 patients with BD and 30 healthy controls, matched for gender and age. Biochemical parameters evaluated included homocysteine (Hcy), folic acid, vitamin B12, ferritin, creatine kinase (CK) and C-reactive protein (CRP). RESULTS: Hcy levels were significantly higher in the BD patients, both during mania and after achieving euthymia. When Hcy was adjusted for body mass index, there was no significant difference between patients and controls. Ferritin was the only marker that showed a significant decrease during mania when compared to both euthymic patients and controls. There were no significant differences for folate, vitamin B12, CK and CRP. CONCLUSIONS: These findings do not show an association between alterations of markers of cardiovascular risk during manic episodes. Further studies are necessary to determine factors and mechanisms associated with cardiovascular risk in patients with BD.

Homocysteine and other markers of cardiovascular risk during a manic episode in patients with bipolar disorder

Objective: To evaluate serum levels of different biomarkers associated with cardiovascular disease in patients with bipolar disorder (BD). Patients were prospectively evaluated in two separate instances: during acute mania and after remission of manic symptoms. All measurements were compared with those of healthy controls. Methods: The study included 30 patients with BD and 30 healthy controls, matched for gender and age. Biochemical parameters evaluated included homocysteine (Hcy), folic acid, vitamin B12, ferritin, creatine kinase (CK) and C-reactive protein (CRP). Results: Hcy levels were significantly higher in the BD patients, both during mania and after achieving euthymia. When Hcy was adjusted for body mass index, there was no significant difference between patients and controls. Ferritin was the only marker that showed a significant decrease during mania when compared to both euthymic patients and controls. There were no significant differences for folate, vitamin B12, CK and CRP. Conclusions: These findings do not show an association between alterations of markers of cardiovascular risk during manic episodes. Further studies are necessary to determine factors and mechanisms associated with cardiovascular risk in patients with BD. .

Pharmacological treatment of bipolar depression: qualitative systematic review of double-blind randomized clinical trials.

Randomized clinical trial (RCT) is the best study design for treatment-related issues, yet these studies may present a number of biases and limitations. The objective of this study is to carry out a qualitative analysis of RCT methodology in the treatment of bipolar depression (BD). A systematic review covering the last 20 years was performed on PubMed selecting double-blind RCTs for BD. The identification items of the articles, their design, methodology, outcome and grant-related issues were all analyzed. Thirty articles were included, all of which had been published in journals with an impact factor >3. While almost half studies (46.7%) used less than 50 patients as a sample, 70% did not describe or did not perform sample size calculation. The Last Observation Carried Forward (LOCF) method was used in 2/3 of the articles and 53.4% of the studies had high sample losses (>20%). Almost half the items were sponsored by the pharmaceutical industry and 33.3% were sponsored by institutions or research foundations. Articles on the pharmacological treatment of BD have several limitations which hinder the extrapolation of the data to clinical practice. Methodological errors and biases are common and statistical simplifications compromise the consistency of the findings.

Effect of a nanostructured dendrimer-naloxonazine complex on endogenous opioid peptides µ1 receptor-mediated post-ictal antinociception.

The aim of this study was to investigate the capacity of the host dendrimer DAB-Am-16 as a drug carrier to reduce the time required for the encapsulated naloxonaxine to establish an irreversible covalent bond with µ(1)-opioid receptor (resulting in a pharmacologically selective effect). The efficacy of dendrimer-naloxonazine nanocomplex (DNC) was studied in antinociception induced by convulsions elicited by intraperitoneal (IP) administration of pentylenetetrazole, and analgesia was measured by the tail-flick test. We found that animals showed increased tail-flick latencies following convulsions. Furthermore, acute pre-treatment (10 minutes) with DNC, but not with naloxonazine alone, antagonized post-ictal analgesia in comparison with control pre-treatment. However, naloxonazine treatment 24 hours before PTZ decreased post-ictal antinociception, but DNC failed to antagonize tonic-clonic seizure-induced analgesia. In addition, according to Racine's index of seizure severity, naloxonazine, DAB-Am-16 dendrimer or DNC did not influence seizure severity when administered either 10 minutes or 24 hours before PTZ. FROM THE CLINICAL EDITOR: This study characterizes the effect of a dendrimer-naloxonazine complex on µ1 receptor-mediated post-ictal antinociception in an animal model of seizure disorder.

Prevalência de sintomas depressivos em uma amostra de prostitutas de Porto Alegre / Prevalence of depressive symptoms in a sample of prostitutes in Porto Alegre

INTRODUÇÃO: a prevalência de transtornos depressivos na população feminina de Porto Alegre é estimada em 14,5 por cento. Não existem relatos sobre a prevalência de sintomas ou transtornos depressivos entre as prostitutas, população de risco para transtornos mentais. OBJETIVOS: quantificar a prevalência de sintomas depressivos em amostra de prostitutas de Porto Alegre e fatores associados. MATERIAL E MÉTODOS: uma amostra consecutiva e não aleatória de 97 mulheres entre 18 e 60 anos, cadastradas na Organização Não Governamental Núcleo de Estudos da Prostituição (NEP), de Porto Alegre, foi estudada. Após consentimento informado, as entrevistadas foram investigadas através do Inventário para depressão de Beck (BDI). O ponto de corte igual ou maior que 13 foi utilizado para detecção de sintomas depressivos. RESULTADOS: na amostra estudada, a idade média foi de 29,6 anos (dp 8,5 anos); 67 por cento apresentaram sintomas depressivos (ponto de corte³ 13) com escore médio no BDI de 19,1 (dp 10,9); 24,7 por cento da amostra apresentava sintomas leves; 40,2 por cento sintomas moderados e 7,2 por cento sintomas graves. Houve associação estatisticamente significativa entre a presença de sintomas depressivos e uso de álcool, história de doenças sexualmente transmissíveis e ausência de prática religiosa (p<0,05). CONCLUSÃO: além de alta taxa de prevalência de sintomas depressivos (67 por cento), 47,4 por cento das mulheres avaliadas apresentaram níveis moderado e grave de sintomatologia. O uso de álcool, história de doenças sexualmente transmissíveis e ausência de prática religiosa surgiram como fatores associados à presença de sintomas depressivos na amostra estudada.