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The COVID-19 pandemic generated a new dynamic around waste management. Personal protective equipment such as masks, gloves, and face shields were essential to prevent the spread of the disease. However, despite the increase in waste, no technical alternatives were foreseen for the recovery of these wastes, which are made up of materials that can be valued for energy recovery. It is essential to design processes such as waste to energy to promote the circular economy. Therefore, techniques such as pyrolysis and thermal oxidative decomposition of waste materials need to be studied and scaled up, for which kinetic models and thermodynamic parameters are required to allow the design of this reaction equipment. This work develops kinetic models of the thermal degradation process by pyrolysis as an alternative for energy recovery of used masks generated by the COVID-19 pandemic. The wasted masks were isolated for 72 h for virus inactivation and characterized by FTIR-ATR spectroscopy, elemental analysis, and determinate the higher calorific value (HCV). The composition of the wasted masks included polypropylene, polyethylene terephthalate, nylon, and spandex, with higher calorific values than traditional fuels. For this reason, they are susceptible to value as an energetic material. Thermal degradation was performed by thermogravimetric analysis at different heating rates in N2 atmosphere. The gases produced were characterized by gas chromatography and mass spectrometry. The kinetic model was based on the mass loss of the masks on the thermal degradation, then calculated activation energies, reaction orders, pre-exponential factors, and thermodynamic parameters. Kinetics models such as Coats and Redfern, Horowitz and Metzger, Kissinger-Akahira-Sunose were studied to find the best-fit models between the experimental and calculated data. The kinetic and thermodynamic parameters of the thermal degradation processes demonstrated the feasibility and high potential of recovery of these residues with conversions higher than 89.26% and obtaining long-chain branched hydrocarbons, cyclic hydrocarbons, and CO2 as products.
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To take advantage of the residues generated in the production of products from green coffee and due to the special interest in the compounds contained in the bean, a by-product obtained after the extraction of the oil was studied. The physical characterization of the green-coffee-bean by-product was carried out. Subsequently, the extraction of compound 5-CQA was carried out via leaching using central composition design 24 and evaluating factors such as temperature, time, solid/solvent ratio, and ethanol percentage, and its yield was quantified using HPLC. In addition, the response-surface methodology was used to maximize the efficiency of 5-CQA extraction and to perform the kinetic study. Yields of 59 ± 2 mg of 5-CQA/g from the by-product were obtained, and by selecting the best leaching conditions, the kinetic study was performed at 45, 60, and 75 °C, increasing the yield to a total of 61.8 ± 3 mg of 5-CQA/g. By applying the kinetic model of mass transfer, a fit of R2 > 0.97 was obtained, with KLa values between 0.266 and 0.320 min−1. This study showed an approach to optimize the 5-CQA extraction conditions, resulting in a simple, fast, reproducible, accurate, and low-cost method.
Assuntos
Coffea , Cromatografia Líquida de Alta Pressão , Coffea/química , Café/química , Cinética , Extratos Vegetais/químicaRESUMO
Eradication of bovine tuberculosis (bTB) continues to be a worldwide challenge. The lack of reliable vaccines dampens the control and eradication programs of Mycobacterium bovis infection and spread. Selection and breeding of cattle resistant to M. bovis infection would greatly enhance the effectiveness of bTB eradication programs. Here, we have evaluated the potential of serum proteins as biomarkers of cattle resistance to bTB in Holstein-Friesian cows, 6-8-year-old, born and raised in similar conditions in herds with bTB prevalence >30%. Serum proteins obtained from uninfected cows (bTB-resistant; R) were compared to those from infected cows (bTB-susceptible; S), defined by a negative or positive bTB diagnosis, respectively. bTB diagnosis included: (i) single intradermal (caudal fold) tuberculin test, (ii) whole blood IFN-gamma test, (iii) gross visible lesions in lymph nodes and lungs by inspection at the abattoir, and (iv) a bacteriological culture for M. bovis. Using 2D-GE and LC-ESI-MS/MS, we found higher expression levels of primary amine oxidase (AO), complement component 5 (C5), and serotransferrin (TF) in R cattle than S cattle. In-house developed and standardized ELISAs for these novel biomarkers showed the best sensitivities of 72, 77, 77%, and specificities of 94, 94, 83%, for AO, C5, and TF, respectively. AUC-ROC (95% CI) values of 0.8935 (0.7906-0.9964), 0.9290 (0.8484-1.010), and 0.8580 (0.7291-0.9869) were obtained at cut-off points of 192.0, 176.5 ng/ml, and 2.1 mg/ml for AO, C5, and TF, respectively. These proteins are involved in inflammatory/immunomodulatory responses to infections and may provide a novel avenue of research to determine the mechanisms of protection against bTB. Overall, our results indicate that these proteins could be novel biomarkers to help identify cattle resistant to bTB, which in turn could be used to strengthen the effectiveness of existing eradication programs against bTB.
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BACKGROUND: The aim of the study is to characterize a biomedical magnesium alloy and highlighting the loss of mechanical integrity due to the sterilization method. Ideally, when using these alloys is to delay the onset of degradation so that the implant can support body loads and avoid toxicological effects due to the release of metal ions into the body. METHODS: Standardized procedures according to ASTM F-1264 and ISO-10993-5 were used, respecting detailed methodological controls to ensure accuracy and reproducibility of the results, this testing methodology is carried out in accordance with the monographs of the Pharmacopoeia for the approval of medical devices and obtaining a health registration. An intramedullary implant (IIM) manufactured in magnesium (Mg) WE43 can support loads of the body in the initial period of bone consolidation without compromising the integrity of the fractured area. A system with these characteristics would improve morbidity and health costs by avoiding secondary surgical interventions. RESULTS: As a property, the fatigue resistance of Mg in aggressive environments such as the body environment undergoes progressive degradation, however, the autoclave sterilization method drastically affects fatigue resistance, as demonstrated in tests carried out under in vitro conditions. Coupled with this phenomenon, the relatively poor biocompatibility of Mg WE43 alloys has limited applications where they can be used due to low acceptance rates from agencies such as the FDA. However, Mg alloy with elements such as yttrium and rare earth elements (REEs) have been shown to delay biodegradation depending on the method of sterilization and the physiological solution used. With different sterilization techniques, it may be possible to keep toxicological effects to a minimum while still ensuring a balance between the integrity of fractured bone and implant degradation time. Therefore, the evaluation of fatigue resistance of WE43 specimens sterilized and tested in immersion conditions (enriched Hank's solution) and according to ASTM F-1264, along with the morphological, crystallinity, and biocompatibility characterization of the WE43 alloy allows for a comprehensive evaluation of the mechanical and biological properties of WE43. CONCLUSIONS: These results will support decision-making to generate a change in the current perspective of biomaterials utilized in medical devices (MDs), to be considered by manufacturers and health regulatory agencies. An implant manufactured in WE43 alloy can be used as an intramedullary implant, considering keeping elements such as yttrium-REEs below as specified in its designation and with the help of a coating that allows increasing the life of the implant in vivo.
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Chronic kidney disease (CKD) causes anemia by renal damage. In CKD, the kidney is submitted to hypoxia, persistent inflammation, leading to fibrosis and permanent loss of renal function. Human recombinant erythropoietin (rEPO) has been widely used to treat CKD-associated anemia and is known to possess organ-protective properties that are independent from its well-established hematopoietic effects. Nonhematopoietic effects of EPO are mediated by an alternative receptor that is proposed to consist of a heterocomplex between the erythropoietin receptor (EPOR) and the beta common receptor (ßcR). The present study explored the effects of rEPO to prevent renal fibrosis in adenine-induced chronic kidney disease (Ad-CKD) and their association with the expression of the heterodimer EPOR/ßcR. Male Wistar rats were randomized to control group (CTL), adenine-fed rats (Ad-CKD), and Ad-CKD with treatment of rEPO (1050 IU/kg, once weekly for 4 weeks). Ad-CKD rats exhibited anemia, uremia, decreased renal function, increased infiltration of inflammatory cells, tubular atrophy, and fibrosis. rEPO treatment not only corrected anemia but reduced uremia and partially improved renal function as well. In addition, we observed that rEPO diminishes tubular injury, prevents fibrosis deposition, and induces the EPOR/ßcR heteroreceptor. The findings may explain the extrahematopoietic effects of rEPO in CKD and provide new strategies for the treatment of renal fibrosis in CKD.
Assuntos
Fibrose/metabolismo , Fibrose/prevenção & controle , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal Crônica/tratamento farmacológico , Animais , Western Blotting , Eritropoetina/uso terapêutico , Imunofluorescência , Humanos , Imunoprecipitação , Masculino , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Receptores da Eritropoetina/metabolismo , Proteínas Recombinantes/uso terapêuticoRESUMO
Gastrointestinal lipase inhibitors are molecules of pharmaceutical interest due to their use as anti-obesity drugs. In this study, forty strains isolated from soil and sediments were identified with the ability to produce inhibition of gastrointestinal lipase activity. The biomass extract of these strains showed at least 50% inhibition in the hydrolysis of tributyrin by recombinant human pancreatic lipase (rHPL) or rabbit gastric lipase (RGL) by in vitro assays. Based on gene sequencing, the isolates were identified mainly as Streptomycetes. Moreover, none of the identified strains has been reported to be lipase inhibitor producers, so they can be viewed as potential sources for obtaining new drugs. IC50 values of the three best inhibitor extracts showed that AC104-10 was the most promising strain for production of gastrointestinal lipase inhibitors. AC104-10 shows 99% homology (16S rRNA gene fragment) to Streptomyces cinereoruber strain NBRC 12756. An inhibitory study over trypsin activity revealed that AC104-10 extract, as well as THL, had no significant effect on the activity of this protease, showing its specificity for lipases. In addition, analyzes by MALDI-TOF mass spectrometry of the enzyme-inhibitor complex revealed that there is a covalent interaction of the AC104-10 inhibitor with the catalytic serine of the pancreatic lipase, and that the molecular weight of the inhibitor is approximately 686.19 Da.
Assuntos
Sedimentos Geológicos/microbiologia , Streptomyces/isolamento & purificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Actinobacteria/metabolismo , Animais , Produtos Biológicos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Humanos , Lagos/microbiologia , Lipase/antagonistas & inibidores , Lipase/metabolismo , RNA Ribossômico 16S , Microbiologia do Solo , Streptomyces/genética , Streptomyces/metabolismoRESUMO
Molecular typing of bacterial isolates provides a powerful approach for distinguishing Mycobacterium bovis (M. bovis) genotypes. It is known that M. bovis strain virulence plays a role in prevalence and spread of the disease, suggesting that strain virulence and prevailing genotypes are associated. However, it is not well understood whether strain virulence correlates with particular genotypes. In this study, we assessed the in vitro intracellular growth of 18 M. bovis isolates in bovine macrophages as an indicator of bacterial virulence and sought a relationship with the genotype identified by spoligotyping. We found 14 different spoligotypes-11 were already known and three spoligotypes had never been reported before. We identified 2 clusters that were phylogenetically related, containing 10 and 6 strains, respectively, and 2 orphan strains. Intracellular growth and phagocytic rates of 18 M. bovis strains were heterogeneous. Our results suggest that M. bovis intracellular growth and phagocytosis are independent of the bacterial lineage identified by spoligotyping.
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Mycobacterium bovis, the causative agent of bovine tuberculosis (TB), is a successful pathogen that remains an important global threat to livestock. Cattle naturally exposed to M. bovis normally become reactive to the M. bovis-purified protein derivative (tuberculin) skin test; however, some individuals remain negative, suggesting that they may be resistant to infection. To better understand host innate resistance to infection, 26 cattle from herds with a long history of high TB prevalence were included in this study. We investigated the bactericidal activity, the production of reactive oxygen and nitrogen species and the TB-related gene expression profile after in vitro M. bovis challenge of monocyte-derived macrophages from cattle with TB (n=17) and from non-infected, exposed cattle (in-contacts, n=9). The disease status was established based on the tuberculin skin test and blood interferon-gamma test responses, the presence of visible lesions at inspection on abattoirs and the histopathology and culture of M. bovis. Although macrophages from TB-infected cattle enabled M. bovis replication, macrophages from healthy, exposed cattle had twofold lower bacterial loads, overproduced nitric oxide and had lower interleukin (IL)-10 gene expression (P⩽0.05). Higher mRNA expression levels of inducible nitric oxide synthase, C-C motif chemokine ligand 2 and IL-12 were observed in macrophages from all in-contact cattle than in macrophages from their TB-infected counterparts, which expressed more tumour necrosis factor-α; however, the differences were not statistically significant owing to individual variation. These results confirm that macrophage bactericidal responses have a crucial role in innate resistance to M. bovis infection in cattle.
Assuntos
Macrófagos/imunologia , Macrófagos/microbiologia , Mycobacterium bovis/fisiologia , Tuberculose Bovina/imunologia , Tuberculose Bovina/microbiologia , Animais , Bovinos , Sobrevivência Celular , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Feminino , Regulação da Expressão Gênica , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-12/genética , Interleucina-12/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Fagocitose , Superóxidos/metabolismo , Tuberculose Bovina/genética , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
To identify the resistance phenotype against Mycobacterium bovis in cattle, we used a bactericidal assay that has been considered a marker of this trait. Three of 24 cows (12.5%) were phenotyped as resistant and 21 as susceptible. Resistance of bovine macrophages (MΦ) to BCG challenge was evaluated for its association with SLC11A1 GT microsatellite polymorphisms within 3'UTR region. Twenty-three cows (95.8%) had a GT13 genotype, reported as resistant, consequently the SLC11A1 polymorphism was not in agreement with our bactericidal assay results. MΦ of cows with resistant or susceptible phenotype were challenged in vitro with virulent M. bovis field strain or BCG, and nitric oxide production, bacterial killing and apoptosis induction were measured in resting and LPS-primed states. M. bovis field strain induced more apoptosis than BCG, although the difference was not significant. Resistant MΦ controlled better the replication of M. bovis (P<0.01), produced more nitric oxide (P<0.05) and were slightly more prone to undergo apoptosis than susceptible cells. LPS pretreatment of MΦ enhanced all the functional parameters analyzed. Inhibition of nitric oxide production with n (G)-monomethyl-L-arginine monoacetate enhanced replication of M. bovis but did not modify apoptosis rates in both resistant and susceptible MΦ. We conclude that nitric oxide production not apoptosis is a major determinant of macrophage resistance to M. bovis infection in cattle and that the influence of SLC11A1 gene 3'UTR polymorphism is not associated with this event.
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Apoptose/fisiologia , Macrófagos/microbiologia , Mycobacterium bovis/patogenicidade , Óxido Nítrico/fisiologia , Regiões 3' não Traduzidas , Animais , Sequência de Bases , Bovinos , Primers do DNA , Feminino , Óxido Nítrico/biossíntese , Reação em Cadeia da Polimerase , Polimorfismo GenéticoRESUMO
The growing incidence of obesity is a worldwide public health problem leading to a risk factor for non-alcoholic fatty liver disease, which extends from steatosis to steatohepatitis and cirrhosis. We investigated whether the aqueous extract of Hibiscus sabdariffa L. (Hs) reduces body weight gain and protects the liver by improving lipid metabolism in high fat diet-induced obese C57BL/6NHsd mice. We found that oral administration of the Hs extract reduced fat tissue accumulation, diminished body weight gain and normalized the glycemic index as well as reduced dyslipidemia compared to the obese mice group that did not receive Hs treatment. In addition, Hs treatment attenuated liver steatosis, down-regulated SREBP-1c and PPAR-γ, blocked the increase of IL-1, TNF-α mRNA and lipoperoxidation and increased catalase mRNA. Our results suggest that the anti-obesity, anti-lipidemic and hepatoprotective effects of the Hs extract are related to the regulation of PPAR-γ and SREBP-1c in the liver.
Assuntos
Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/metabolismo , Hibiscus/química , Obesidade/complicações , PPAR gama/genética , Extratos Vegetais/administração & dosagem , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Animais , Fármacos Antiobesidade/administração & dosagem , Regulação para Baixo/efeitos dos fármacos , Fígado Gorduroso/etiologia , Fígado Gorduroso/genética , Interleucina-1/genética , Interleucina-1/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Hepatopatia Gordurosa não Alcoólica , Obesidade/metabolismo , PPAR gama/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Triglicerídeos/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
La epilepsia del lóbulo temporal es la forma más común de epilepsia que padece el ser humano. El sustrato fisiopatológico que la caracteriza es la esclerosis del hipocampo, que se distingue por pérdida neuronal, gliosis y disminución del volumen del hipocampo y áreas vecinas como la amígdala, el giro parahipocámpico y la corteza entorrinal. Lo anterior ocasiona atrofia y esclerosis del hilus del giro dentado y de las áreas CA1 y CA3 del hipocampo. Además se establece cierta reorganización de las vías neuronales que favorecen la neoespinogénesis, la morfogénesis, la neosinaptogénesis y la neurogénesis, con desarrollo aberrante de células y fibras, que contribuyen a la formación de un foco cuyo componente neuronal muestra un significativo aumento en la excitabilidad. El interés por entender el proceso de la epileptogénesis ha motivado al diseño de modelos de este tipo de epilepsia en animales de experimentación. La epileptogénesis evoluciona en el tiempo y muestra que la reorganización dinámica de las vías neuronales establece una red neuronal con cambios funcionales y anatómicos muy significativos. En este trabajo se realiza una revisión de la información obtenida por estudios electrofisiológicos que combinan el marcaje celular mediante el registro intra o extracelular en el hipocampo y en particular de las áreas CA1 y CA3 involucradas estrechamente con la epileptogénesis.
Temporal Lobe Epilepsy is the most common form of human epilepsy. Hippocampal sclerosis, neuronal loss, gliosis and hippocampal volume reduction are the representative changes of this pathology. Also some other near areas like amygdala, gyrus parahipocampal and entorrinal cortex are affected. Furthermore the neural circuits undergo activity-dependent reorganization during epileptogenesis. This brain circuits remodeling include neuronal loss (acute and delayed), neurogenesis, gliosis, plasticity (axonal and dendritic), inflammation and molecular reorganization. Two significant changes are evident, aberrant sprouting of granule cell axons in the dentate gyrus and hilar ectopic granular cells. Because temporal lobe epilepsy commonly develops after brain injury, most experimental animal models involve use of this factor. The pilocarpine-induced status epilepticus rat model may be the most widely used model of temporal lobe epilepsy. In the present work, we review the experimental support for seizure-induced plasticity in neural circuits, and then turn to evidence that seizure-induced plasticity occurs in human temporal-lobe.
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In this work we examined the correlation between long-term glial resilience and slow epileptogenesis using the pilocarpine-insult rat model. We assessed, quantitatively and morphometrically, glial fibrillary acidic protein (GFAP) expression and cell densities in hippocampus in a dose-response manner 2, 4 and 8 weeks after the pilocarpine insult. GFAP changes were correlated with observations on microglial activation. We used a commonly applied epileptogenic pilocarpine dose (380mg/kg) and its fractions of 1/10, 1/4 and 1/2. GFAP expression evaluated at 2 weeks revealed dose-dependent cytoskeletal hypertrophy and loss of GFAP+ cell densities in hippocampus. At 4-week timepoint, recoveries of the above mentioned parameters were observed in all groups, except for the full dose group in which the astrocytic hypertrophy reached the highest level, while its density dropped to the lowest level. Strong and localized microgliosis revealed by CD11b immunoreactivity was observed in hilus in the full dose group at 2- and 4-, persisting at 8-week timepoints. Through changing pattern analysis, we conclude that the loss of astroglial resilience is likely to be a determining factor for spontaneous recurrent seizure onset.
Assuntos
Astrócitos/metabolismo , Citoesqueleto/metabolismo , Epilepsia/metabolismo , Hipocampo/metabolismo , Animais , Epilepsia/induzido quimicamente , Proteína Glial Fibrilar Ácida/metabolismo , Masculino , Neurônios/metabolismo , Pilocarpina , Ratos , Ratos WistarRESUMO
Human and bovine tuberculosis (TB) are currently a serious health problem in Latin America. Although the causal agents were discovered more than one century ago, the control of these illnesses is still beyond our reach: human TB accounts for more than one hundred deaths each day in this region, whereas bovine TB represents a public health risk as well as a major economic problem. We herein analyze the situation of human and bovine TB in Latin America, and present studies from our laboratories on bacterial virulence factors, intrinsic resistance features in the host, and the protective response induced in cattle through vaccination or immunization. Finally, the convenience for implementing and/or revising the use of currently available tools for TB control in the region is discussed.
Assuntos
Mycobacterium tuberculosis/patogenicidade , Tuberculose/prevenção & controle , Tuberculose/veterinária , Animais , Vacina BCG , Bovinos , Humanos , América Latina , Tuberculose/microbiologiaRESUMO
Technological advances in the medical area have allowed for development of useful techniques to treat patients with diverse diseases. For example, at intensive care units this technology allows maintenance blood flow and tissue oxygenation even when brain death (BD) is already established and the individual cannot function. The function of heart, lungs, and other organs can be maintained with different devices, but maintenance of cerebral functions is not not yet possible. Therefore, when a subject fulfills legal and medical requirements for BD, we must be clear that any patient procedure will not keep him alive, although the subject looks alive due to support devices; when BD is present, death must be accepted. Obviously, death is a difficult process to accept, including for health personnel. We consider that it is very important for medical and nursing personnel directly responsible for patient care to receive knowledge on BD and recognize the alternatives with regard this situation, to be able to provide specific orientation when it is required. This paper is a review of the BD concept, main physiopathologic changes, and some possible treatment alternatives to maintain the patient as a potential organ donor.
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Morte Encefálica/fisiopatologia , Morte Encefálica/diagnóstico , Humanos , Mudanças Depois da MorteRESUMO
Los avances tecnológicos en el área médica han permitido el desarrollo de técnicas útiles en la terapia de sujetos que padecen diversas entidades patológicas. Por ejemplo, en las unidades de terapia intensiva dicha tecnología permite la conservación del riego sanguíneo y la oxigenación de los tejidos, aun cuando la muerte encefálica (ME) ya ha ocurrido y el individuo no pueda volver a funcionar como un ser vivo, pues las funciones del corazón, los pulmones y otros órganos, pueden ser sustituidas con aparatos, pero las funciones cerebrales todavía no. Por lo tanto cuando un sujeto cubre los requisitos establecidos médica y legalmente para el diagnóstico de ME, se debe tener bien claro que cualquier medida que se siga aplicando al paciente ya no tendrá ningún objeto para mantener su vida, y aunque el sujeto parece vivo por las medidas de soporte a las que está sometido, cuando la ME se establece, se debe aceptar como muerte definitiva del individuo. Desde luego, como en todos los casos de muerte, se trata de un proceso difícil de admitir, inclusive para el personal de salud; sin embargo, consideramos que es de suma importancia que principalmente el equipo médico y de enfermería, que son los responsables directos de la atención de los enfermos en el área clínica, estén bien informados al respecto para saber las alternativas que existen con los sujetos en ME y poder orientar adecuadamente a quien lo necesite. En el presente trabajo realizamos una revisión bibliográfica sobre el concepto de ME, los principales cambios fisiopatológicos que presenta el sujeto y algunas posibles alternativas de tratamiento para mantenerlo como potencial donador de órganos.
Technological advances in the medical area have allowed for development of useful techniques to treat patients with diverse diseases. For example, at intensive care units this technology allows maintenance blood flow and tissue oxygenation even when brain death (BD) is already established and the individual cannot function. The function of heart, lungs, and other organs can be maintained with different devices, but maintenance of cerebral functions is not not yet possible. Therefore, when a subject fulfills legal and medical requirements for BD, we must be clear that any patient procedure will not keep him alive, although the subject looks alive due to support devices; when BD is present, death must be accepted. Obviously, death is a difficult process to accept, including for health personnel. We consider that it is very important for medical and nursing personnel directly responsible for patient care to receive knowledge on BD and recognize the alternatives with regard this situation, to be able to provide specific orientation when it is required. This paper is a review of the BD concept, main physiopathologic changes, and some possible treatment alternatives to maintain the patient as a potential organ donor.
Assuntos
Humanos , Morte Encefálica/fisiopatologia , Morte Encefálica/diagnóstico , Mudanças Depois da MorteRESUMO
Se presenta un estudio biomecánico comparativo entre el clavo endomedular retrógrado y el tornillo condíleo dinámico Las fracturas supracondíleas de fémur presentan un problema de difícil solución para los cirujanos ortopedistas. Actualmente es aceptado que el tratamiento quirúrgico es el de elección ; dentro del mismo disponemos del tornillo condíleo dinámico (DCS) cmo uno de los más utilizados, y últimamente el clavo endomedular retrógrado como una buena alternativa de tratamiento. El clavo endomedular tendría ventajas biomecánicas basadas en la posición intramedular a lo largo del eje axial del fémur, pero esta hipótesis no pudo ser comprobada por los trabajos realizados, ya que todos los autores comunican similares resultados. Por eso el objeto de este trabajo es realizar un estudio biomecánico entre ambos métodos. Para este estudio se utilizaron 6 fémures cadavéricos frescos, no formolizados, con ausencia de lesiones patológicas. Se realizaron osteotomías a 7 cm. proximal de la línea condílea, se efectuaron osteosíntesis con DCS en 3 fémures y clavo endomedular retrógrado en los 3 restantes. Se utilizó un extensómetro como método de registro y para las pruebas de movilización y carga se empleó la máquina GENU II. Se realizaron pruebas con carga axial constante en ambas rotaciones, varo-valgo y flexión. Como conclusión, en nuestro estudio biomec nico encontramos que el DCS presenta mayor estabilidad en las pruebas realizadas, excepto en flexión
Assuntos
Estudo Comparativo , Humanos , Fraturas do Fêmur/cirurgia , Fixação Interna de Fraturas , Fixação Intramedular de Fraturas , Pinos Ortopédicos , Parafusos Ósseos , Argentina , AutopsiaRESUMO
Se presenta un estudio biomecánico comparativo entre el clavo endomedular retrógrado y el tornillo condíleo dinámico Las fracturas supracondíleas de fémur presentan un problema de difícil solución para los cirujanos ortopedistas. Actualmente es aceptado que el tratamiento quirúrgico es el de elección ; dentro del mismo disponemos del tornillo condíleo dinámico (DCS) cmo uno de los más utilizados, y últimamente el clavo endomedular retrógrado como una buena alternativa de tratamiento. El clavo endomedular tendría ventajas biomecánicas basadas en la posición intramedular a lo largo del eje axial del fémur, pero esta hipótesis no pudo ser comprobada por los trabajos realizados, ya que todos los autores comunican similares resultados. Por eso el objeto de este trabajo es realizar un estudio biomecánico entre ambos métodos. Para este estudio se utilizaron 6 fémures cadavéricos frescos, no formolizados, con ausencia de lesiones patológicas. Se realizaron osteotomías a 7 cm. proximal de la línea condílea, se efectuaron osteosíntesis con DCS en 3 fémures y clavo endomedular retrógrado en los 3 restantes. Se utilizó un extensómetro como método de registro y para las pruebas de movilización y carga se empleó la máquina GENU II. Se realizaron pruebas con carga axial constante en ambas rotaciones, varo-valgo y flexión. Como conclusión, en nuestro estudio biomec nico encontramos que el DCS presenta mayor estabilidad en las pruebas realizadas, excepto en flexión
Assuntos
Humanos , Argentina , Pinos Ortopédicos , Fixação Interna de Fraturas , Fixação Intramedular de Fraturas , Fraturas do Fêmur/cirurgia , Parafusos Ósseos , AutopsiaRESUMO
Despúes de un periodo de isquemia cerebral se observa aumento en la frecuencia de descarga neuronal de hipocampo y signos electroencefalográficos de actividad paroxística espontánea. Es probable que estos cambios en la excitabilidad se deban a mecanismos de excitotoxicidad que inducen muerte neuronal. En el presente estudio se evaluaron los cambios en la inhibición recurrente así como en la densidad neuronal del hipocampo de ratas sometidas a 5 y 20 min de isquemia focal con un periodo de recuperación de 7 días. El grado de inhibición recurrente se cuantificó mediante el índice de máxima inibición (IMI). La cuantificación neuronal se realizó a través de un sistema de procesamiento digital de imágenes (Imagenia 2000). Se observó aumento en la amplitud del segundo componente del segundo potencial provocado. Al calcular el IMI resultó mayor que 1. La mayor pérdida neuronal se observó en CA1 y CA2, mientras que la mayor vulnerabilidad se observó en el GD, CA3 y CA4. En conclusión, la isquemia focal con recuperación de 7 días provocó disminución en la densidad neuronal así como la aparición de un mecanismo de desinhibición, que condiciona cambios en la excitabilidad neuronal del hipocampo probablemente debido a lesión de interneuronas
Assuntos
Animais , Ratos , Hipocampo/irrigação sanguínea , Hipocampo/lesões , Hipocampo/fisiopatologia , Isquemia/complicações , Isquemia/fisiopatologia , Excitação Neurológica/patologia , Neurônios/patologia , Neurônios/ultraestruturaRESUMO
La 4-hidroxi 4-etil butiramida (HEPB) y la 3-hidroxi, 3-etil, 3-fenil propionamida (HEPB) han mostrado propiedades anticonvulsivas en algunos modelos experimentales de epilepsia. El objetivo del presente trabajo fue la evaluación de estas sustancias en ratas en las que se provocó el cambio permanente de la excitabilidad neuronal mediante la estimulación eléctrica de la amígdala del lóbulo temporal o la corteza entorrinal. Asimismo, se provocaron cambios de la excitabilidad neuronal por la aplicación local de picrotoxina. En animales anestesiados con uretano (1.0-1.5g kg ip) e inmovilizados con bromuro de pancuronio se implantaron electrodos a permanencia con la técnica de estereotaxia. En un grupo de animales se provocó el cambio en el umbral convulsivo por la aplicación de estímulos eléctricos en el núcleo amigdalino (tren de pulsos de 1 seg; pulso bifásico 0.5 mseg de duración, 60 Hz de frecuencia y 250 µA de intensidad) cada hora, hasta provocar una posdescarga con duración de 50 a 60 seg. En otro grupo de ratas se provocó el cambio por la aplicación de estímulos eléctricos en el hipocampo dorsal con la finalidad de inducrir crisis hipocampales rápidamente recurrentes para asegurar el establecimiento del fenómeno de kindling. Otro procedimiento utilizado en este estudio fue la prueba de los pulsos pares con la cual se valoraron los cambios provocados en la inhibición recurrente del giro dentado después de la estimulación interativa de la corteza entorinal. En todas las condiciones experimentales se encontraron cambios significativos, tales como aumento en la duración de la posdescarga y disminución de la inhibición recurrente. Se midió la relación entre la amplitud del potencial de la población de espigasprovocadas por el segundo estímulo o prueba PN (T) y la amplitud del primer potencial provocado por el estímulo condicionante PN (C). Con la razón PN (T)/PN (C) se obtuvo el ®índice de máxima inhibición¼. La HEPB y la HEPP provocaron disminución significativa de la duración de la posdescarga. Además, la inhibición recurrente mostró en todos los casos, cambios muy significativos, ya que después de la administración de ambas sustancias el IMI siempre mostró valores menores de 1 incluso en los animales con crisis hipocampales establecidas. La magnitud de estos efectos fueron claramente relacionados con la dosis administrada. Estos resultados sugieren que tanto la HEPB y la HEPP aumentan la inhibición mediada por los receptores GABA