RESUMO
INTRODUCTION: The aim of study was to assess the impact of an enhanced recovery after surgery (ERAS) protocol and minimally invasive approaches on short-term outcomes in rectal surgery. PATIENTS AND METHODS: A consecutive series of patients that underwent open or minimally invasive rectal resections in a single institution between January 2015 and April 2020 were included in the study. An ERAS program was introduced in April 2016. The study cohort was divided into three groups: open surgery without ERAS, open surgery with ERAS, and minimally invasive surgery with ERAS. Outcome measures compared were recovery parameters, surgical stress parameters, 30-day morbidity and mortality, oncological radicality and length of hospital stay. RESULTS: A total of 202 patients were included: 43 in the open non-ERAS group, 92 in the open ERAS group and 67 in the minimally invasive ERAS group. All recovery parameters apart from postoperative nausea and vomiting were significantly improved in both ERAS groups. Surgical stress parameters, prolonged postoperative ileus, and hospital stay were significantly reduced in the minimally invasive ERAS group. The overall 30-day morbidity and mortality and oncological radicality did not significantly differ among the three groups. CONCLUSIONS: Minimally invasive approaches and enhanced recovery care in rectal surgery improve short-term outcomes. Their combination leads to an improvement in recovery parameters and a reduction of prolonged postoperative ileus and hospital stay.
Assuntos
Procedimentos Cirúrgicos do Sistema Digestório , Recuperação Pós-Cirúrgica Melhorada , Íleus , Laparoscopia , Humanos , Assistência Perioperatória/métodos , Intestinos , Procedimentos Cirúrgicos do Sistema Digestório/métodos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Procedimentos Cirúrgicos Minimamente Invasivos/efeitos adversos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Íleus/etiologia , Tempo de Internação , Laparoscopia/métodosRESUMO
Amyloid A amyloidosis is a serious clinical condition resulting from the systemic deposition of amyloid A originating from serum amyloid A proteins with the kidneys being the most commonly and earliest affected organ. Previously described amyloid A amyloidosis is linked to increased production and deposition of serum amyloid A proteins secondary to inflammatory conditions arising from infectious, metabolic, or genetic causes. Here we describe a family with primary amyloid A amyloidosis due to a chr11:18287683 T>C (human genome version19) mutation in the SAA1 promoter linked to the amyloidogenic SAA1.1 haplotype. This condition leads to a doubling of the basal SAA1 promoter activity and sustained elevation of serum amyloid A levels that segregated in an autosomal dominant pattern in 12 genetically affected and in none of six genetically unaffected relatives, yielding a statistically significant logarithm of odds (LOD) score over 5. Affected individuals developed proteinuria, chronic kidney disease and systemic deposition of amyloid composed specifically of the SAA1.1 isoform. Tocilizumab (a monoclonal antibody against the interleukin-6 receptor) had a beneficial effect when prescribed early in the disease course. Idiopathic forms represent a significant and increasing proportion (15-20%) of all diagnosed cases of amyloid A amyloidosis. Thus, genetic screening of the SAA1 promoter should be pursued in individuals with amyloid A amyloidosis and no systemic inflammation, especially if there is a positive family history.
Assuntos
Amiloidose , Amiloidose/complicações , Humanos , Mutação , Regiões Promotoras Genéticas , Proteína Amiloide A Sérica/genética , Proteína Amiloide A Sérica/metabolismoRESUMO
The incidence of cutaneous malignant melanoma is increasing worldwide. While the treatment of initial stages of the disease is simple, the advanced disease frequently remains fatal despite novel therapeutic options . This requires identification of novel therapeutic targets in melanoma. Similarly to other types of tumours, the cancer microenvironment plays a prominent role and determines the biological properties of melanoma. Importantly, melanoma cell-produced exosomes represent an important tool of intercellular communication within this cancer ecosystem. We have focused on potential differences in the activity of exosomes produced by melanoma cells towards melanoma-associated fibroblasts and normal dermal fibroblasts. Cancer-associated fibroblasts were activated by the melanoma cell-produced exosomes significantly more than their normal counterparts, as assessed by increased transcription of genes for inflammation-supporting cytokines and chemokines, namely IL-6 or IL-8. We have observed that the response is dependent on the duration of the stimulus via exosomes and also on the quantity of exosomes. Our study demonstrates that melanoma-produced exosomes significantly stimulate the tumour-promoting proinflammatory activity of cancer-associated fibroblasts. This may represent a potential new target of oncologic therapy .
Assuntos
Exossomos/metabolismo , Fibroblastos/metabolismo , Melanoma Experimental/metabolismo , Fibroblastos/patologia , Humanos , Melanoma Experimental/patologia , Células Tumorais CultivadasRESUMO
Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) represents an autoimmunity disease characterized by high mortality. For successful treatment, the detailed knowledge of its complex pathogenesis and the set of biomarkers for differential diagnostics are desired. Analysis of molecular content of small urinary extracellular vesicles (uEV) offers the possibility to find markers in the form of microRNAs (miRNAs) and study the pathways involved in pathogenesis. We used next-generation sequencing in the first preliminary study to detect the miRNAs with altered expression in uEVs of patients with AAV in comparison with age-matched controls. We confirmed the results using single-target quantitative polymerase chain reaction tests on different sets of samples and found five miRNAs (miR-30a-5p, miR-31-3p, miR-99a-5p, miR-106b-5p, miR-182-5p) with highly elevated levels in uEVs of patients. We performed the comparison of their targets with the differentially expressed proteins in uEVs of patients included in the first phase. We realized that upregulated miRNAs and proteins in uEVs in AAV patients target different biological pathways. The only overlap was detected in pathways regulating the actin cytoskeleton assembly and thus potentially affecting the glomerular functions. The associations of upregulated miRNAs with pathways that were neglected as components of complex AAV pathogenesis, e.g., the epidermal growth factor receptor signaling pathway, were found.
Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos , Vesículas Extracelulares , MicroRNAs , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/genética , Biomarcadores , Vesículas Extracelulares/genética , Humanos , Rim , MicroRNAs/genéticaRESUMO
Erythropoietin (EPO) downregulates hepcidin expression to increase the availability of iron; the downregulation of hepcidin is mediated by erythroferrone (ERFE) secreted by erythroblasts. Erythroblasts also express transferrin receptor 2 (TFR2); however, the possible role of TFR2 in hepcidin downregulation is unclear. The purpose of the study was to correlate liver expression of hepcidin with the expression of ERFE and TFR2 in murine bone marrow and spleen at 4, 16, 24, 48, 72 and 96 h following administration of a single dose of EPO. Splenic Fam132b expression increased 4 h after EPO injection; liver hepcidin mRNA was decreased at 16 h. In the spleen, expression of TFR2 and transferrin receptor (TFR1) proteins increased by an order of magnitude at 48 and 72 h after EPO treatment. The EPO-induced increase in splenic TFR2 and TFR1 was associated with an increase in the number of Tfr2- and Tfr1-expressing erythroblasts. Plasma exosomes prepared from EPO-treated mice displayed increased amount of TFR1 protein; however, no exosomal TFR2 was detected. Overall, the results confirm the importance of ERFE in stress erythropoiesis, support the role of TFR2 in erythroid cell development, and highlight possible differences in the removal of TFR2 and TFR1 from erythroid cell membranes.
Assuntos
Eritropoetina/farmacologia , Receptores da Transferrina/genética , Animais , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Eritroblastos/efeitos dos fármacos , Eritroblastos/metabolismo , Exossomos/metabolismo , Hepcidinas/genética , Hepcidinas/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Receptores da Transferrina/metabolismo , Baço/metabolismoRESUMO
Matriptase-2, a serine protease expressed in hepatocytes, is a negative regulator of hepcidin expression. The purpose of the study was to investigate the interaction of matriptase-2 with hemojuvelin protein in vivo. Mice lacking the matriptase-2 proteolytic activity (mask mice) display decreased content of hemojuvelin protein. Vice versa, the absence of hemojuvelin results in decreased liver content of matriptase-2, indicating that the two proteins interact. To further characterize the role of matriptase-2, we investigated iron metabolism in mask mice fed experimental diets. Administration of iron-enriched diet increased liver iron stores as well as hepcidin expression. Treatment of iron-overloaded mask mice with erythropoietin increased hemoglobin and hematocrit, indicating that the response to erythropoietin is intact in mask mice. Feeding of an iron-deficient diet to mask mice significantly increased spleen weight as well as the splenic content of erythroferrone and transferrin receptor proteins, indicating stress erythropoiesis. Liver hepcidin expression was decreased; expression of Id1 was not changed. Overall, the results suggest a complex interaction between matriptase-2 and hemojuvelin, and demonstrate that hepcidin can to some extent be regulated even in the absence of matriptase-2 proteolytic activity.
Assuntos
Proteínas Ligadas por GPI/fisiologia , Proteína da Hemocromatose/fisiologia , Sobrecarga de Ferro/metabolismo , Proteínas de Membrana/fisiologia , Serina Endopeptidases/fisiologia , Animais , Proteína Morfogenética Óssea 6/biossíntese , Proteína Morfogenética Óssea 6/genética , Eritropoetina/farmacologia , Feminino , Proteínas Ligadas por GPI/biossíntese , Proteínas Ligadas por GPI/deficiência , Proteínas Ligadas por GPI/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína da Hemocromatose/biossíntese , Proteína da Hemocromatose/deficiência , Proteína da Hemocromatose/genética , Hepcidinas/biossíntese , Hepcidinas/genética , Proteína 1 Inibidora de Diferenciação/biossíntese , Proteína 1 Inibidora de Diferenciação/genética , Deficiências de Ferro , Ferro da Dieta/farmacologia , Fígado/metabolismo , Masculino , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Especificidade de Órgãos , Regiões Promotoras Genéticas/genética , Domínios Proteicos , Proteínas Recombinantes/metabolismo , Serina Endopeptidases/deficiência , Serina Endopeptidases/genética , Baço/metabolismoRESUMO
Hemicorporectomy is the amputation of the lower body - pelvis and lower limbs. It requires transection of the spine and dural sac at the level of aortic bifurcation and inferior lower vein, and permanent urinary and stool derivation. Performance indications are tumour trauma and terminal pelvic osteomyelitis. So far about 60 cases have been published; only 11 operations were performed for terminal osteomyelitis. We have successfully performed hemicorporectomy in a patient with chronic sepsis from terminal pelvic osteomyelitis after exhausting all other treatment options. The experience gained and the important moments of the procedure are given in the case report.
Assuntos
Osteomielite , Sepse , Amputação Cirúrgica , Humanos , Osteomielite/cirurgia , Pelve , Sepse/diagnóstico , Sepse/etiologia , Coluna VertebralRESUMO
Post-translational modifications, including phosphorylation, greatly impact the physiological function of proteins, especially those that are natively unfolded and implicated in many neurodegenerative diseases. However, structural and functional studies of such proteins require fully defined phosphorylation, including those that are not physiological. Thus, the kinases ERK2 and GSK-3ß were immobilized to various superparamagnetic beads with carboxylic, aldehyde, Ni2+, or Co3+ functional groups, with a view to efficiently phosphorylate peptides and proteins in vitro. Full phosphorylation of specific synthetic peptides confirmed that beads were successfully loaded with kinases. Remarkably, enzymes covalently immobilized on carboxylated SeraMag beads remained active upon reuse, with residual activity after 10 uses 99.5 ± 0.34% for GSK-3ß and 36.2 ± 2.01% for ERK2. The beads were also used to sequentially phosphorylate recombinant tau, which in vivo is a biomarker of Alzheimer's disease. Thus, a system consisting of two fully active kinases immobilized to magnetic beads is demonstrated for the first time. In comparison to soluble enzymes, the beads are easier to handle, reusable, and thus low-cost. Importantly, these beads are also convenient to remove from reactions to minimize contamination of phosphorylated products or to exchange with other kinases.
Assuntos
Glicogênio Sintase Quinase 3 beta/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Peptídeos/química , Fosforilação , Proteínas tau/química , Animais , Enzimas Imobilizadas , Humanos , Magnetismo , Microesferas , CoelhosRESUMO
Isolated porcine pepsinogen A was used for the preparation of polyclonal rabbit and polyclonal chicken anti-pepsinogen A antibodies. Immunochemical properties of both immunoglobulin fractions were compared. The rabbit anti-serum was further purified using immobilized porcine pepsinogen A on magnetic cellulose beads and the resulting anti-pepsinogen A fraction proved to be applicable for the separation and the determination of porcine pepsinogen A. In contrary, antibodies prepared from chicken eggs by the same way have been found not suitable for the evaluation of the pepsinogen A level. Unexpectedly, the pre-immune fraction of chicken antibodies showed reactivity against porcine pepsinogen A and the affinity separation of specific polyclonal chicken anti-pepsinogen A antibodies on immobilized porcine pepsinogen A did not result in an enrichment of anti-pepsinogen A antibodies.
Assuntos
Anticorpos/imunologia , Mucosa Gástrica/imunologia , Pepsinogênio A/imunologia , Animais , Bovinos , Galinhas , Ensaio de Imunoadsorção Enzimática , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Imuno-Histoquímica , Pepsinogênio A/metabolismo , Coelhos , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/metabolismo , SuínosRESUMO
An infection of any part of female reproductive tract can severely interfere with fertility and reproduction. The fluids and epithelium from the lumen of the female reproductive tract (uterus, oviduct and ovarian follicle) are a known source of antimicrobial action in several species. In this study, we compared the antimicrobial properties of fluids from the reproductive tract of a cow. After removal of small molecules, we demonstrated that there is an antimicrobial activity connected with a fraction of compounds with a molecular mass range between 3500 and 30,000. The most probable candidates responsible for the observed antimicrobial effect were subsequently identified by mass spectroscopy as histones H2A type 2-C, H2B type 1-K, H3.3, and H4. The antimicrobial role of histone H2B was further confirmed by using an antibody against this histone.
Assuntos
Anti-Infecciosos/metabolismo , Genitália Feminina/metabolismo , Histonas/metabolismo , Animais , Líquidos Corporais/metabolismo , Bovinos , Diálise , Eletroforese em Gel de Poliacrilamida , Feminino , Histonas/química , Espectrometria de Massas , Oviductos/metabolismoRESUMO
Magnetic bead cellulose activated with divinyl sulfone was used for the immobilization of Staphylococcus aureus endoproteinase Glu-C (EC 3.4.21.19). The immobilized proteinase was characterized by increased thermostability, by decreased self-cleavage activity, and a possibility of repeated use. The prepared immobilized enzyme was applied for the proteolytic cleavage of α-casein and BSA under different conditions (different composition of buffers, different pH, and different time of digestion). The possibilities of the direct use of enzyme reaction products for MALDI TOF MS analysis were shown.
Assuntos
Proteínas de Bactérias/química , Proteômica/métodos , Serina Endopeptidases/química , Staphylococcus aureus/enzimologia , Caseínas/química , Celulose/química , Estabilidade Enzimática , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Magnetismo , Proteômica/instrumentação , Soroalbumina Bovina/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodosRESUMO
Preparation of affinity polyacrylamide gels containing immobilized Fe(III) ions for the separation of proteins exhibiting metal ion binding properties is described. The presented method enables uniform distribution of immobilized metal ions in the affinity part of the polyacrylamide separating gel. Affinity gels prepared by this way are suitable to follow the effect of different concentrations of metal ions immobilized in polyacrylamide gel on a protein electrophoretic behavior. Polyacrylamide gels containing immobilized Fe(III) ions were used to study the electrophoretic behavior of two model proteins differing in their phosphate group content: chicken ovalbumin and bovine α-casein. For the electrophoretic separation, both the native and the denaturating conditions were used.
Assuntos
Eletroforese em Gel de Poliacrilamida , Compostos Férricos/química , Fosfoproteínas/isolamento & purificação , Íons/química , Fosfoproteínas/químicaRESUMO
ANCA-associated vasculitis (AAV) is a rare, but potentially severe autoimmune disease, even nowadays displaying increased mortality and morbidity. Finding early biomarkers of activity and prognosis is thus very important. Small extracellular vesicles (EVs) isolated from urine can be considered as a non-invasive source of biomarkers. We evaluated several protocols for urinary EV isolation. To eliminate contaminating non-vesicular proteins due to AAV associated proteinuria we used proteinase K treatment. We investigated the differences in proteomes of small EVs of patients with AAV compared to healthy controls by label-free LC-MS/MS. In parallel, we performed an analogous proteomic analysis of urine samples from identical patients. The study results showed significant differences and similarities in both EV and urine proteome, the latter one being highly affected by proteinuria. Using bioinformatics tools we explored differentially changed proteins and their related pathways with a focus on the pathophysiology of AAV. Our findings indicate significant regulation of Golgi enzymes, such as MAN1A1, which can be involved in T cell activation by N-glycans glycosylation and may thus play a key role in pathogenesis and diagnosis of AAV. SIGNIFICANCE: The present study explores for the first time the changes in proteomes of small extracellular vesicles and urine of patients with renal ANCA-associated vasculitis compared to healthy controls by label-free LC-MS/MS. Isolation of vesicles from proteinuric urine samples has been modified to minimize contamination by plasma proteins and to reduce co-isolation of extraluminal proteins. Differentially changed proteins and their related pathways with a role in the pathophysiology of AAV were described and discussed. The results could be helpful for the research of potential biomarkers in renal vasculitis associated with ANCA.
Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos , Vesículas Extracelulares , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/diagnóstico , Cromatografia Líquida , Humanos , Proteômica , Espectrometria de Massas em TandemRESUMO
Understanding the complex factors and mechanisms driving the functioning of coastal ecosystems is vital towards assessing how organisms, ecosystems, and ultimately human populations will cope with the ecological consequences of natural and anthropogenic impacts. Towards this goal, coastal monitoring programs and studies must deliver information on a range of variables and factors, from taxonomic/functional diversity and spatial distribution of habitats, to anthropogenic stress indicators such as land use, fisheries use, and pollution. Effective monitoring programs must therefore integrate observations from different sources and spatial scales to provide a comprehensive view to managers. Here we explore integrating aerial surveys from a low-cost Remotely Piloted Aircraft System (RPAS) with concurrent underwater surveys to deliver a novel approach to coastal monitoring. We: (i) map depth and substrate of shallow rocky habitats, and; (ii) classify the major biotopes associated with these environmental axes; and (iii) combine data from i and ii to assess the likely distribution of common sessile organismal assemblages over the survey area. Finally, we propose a general workflow that can be adapted to different needs and aerial platforms, which can be used as blueprints for further integration of remote-sensing with in situ surveys to produce spatially-explicit biotope maps.
RESUMO
BACKGROUND: Identification of the content of asialotransferrin in the cerebrospinal fluid is a diagnostic method for childhood-onset ataxia and central nervous system hypomyelination (CACH), also known as vanishing white matter disease (VWM), and also for other types of CNS disorders. METHODS: In our work, we have determined the value of the ratio of the asialo form of transferrin to the total transferrin in the CSF using the commercially used Variant(TM) Bio-Rad system for the determination of carbohydrate-deficient transferrin (CDT) in serum. The peak corresponding to the asialo form of transferrin was identified with electrophoresis with subsequent immunofixation and mass spectrometry (MALDI-TOF/TOF). RESULTS: The intra-assay and inter-assay variations of the asialotransferrin value in CSF were 6.8% and 10.2%, respectively. Analysing CSF samples of 60 subjects (23 men aged 22-68 years and 37 women aged 18-77 years) with normal transferrin values and normal cytology as well as biochemistry parameters in the cerebrospinal fluid, and without apparent signs of neurological disorders, we have found the presence of 25.2 +/- 8.2% asialotransferrin. CONCLUSION: Except for the need to obtain approximately 1.5 mL of cerebrospinal fluid and a tenfold concentrating of the sample, there is no need to conduct any modifications of the preparation procedure for the analytic sample and chromatographic separation normally used for serum samples. The HPLC method of asialotransferrin determination in CSF provides clinically useful results.
Assuntos
Assialoglicoproteínas/análise , Assialoglicoproteínas/líquido cefalorraquidiano , Transferrina/análogos & derivados , Adolescente , Adulto , Idoso , Cromatografia Líquida de Alta Pressão/métodos , Feminino , Humanos , Imunoeletroforese , Masculino , Pessoa de Meia-Idade , Isoformas de Proteínas/análise , Isoformas de Proteínas/sangue , Isoformas de Proteínas/líquido cefalorraquidiano , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em Tandem , Transferrina/análise , Transferrina/líquido cefalorraquidiano , Transferrina/metabolismo , Adulto JovemRESUMO
BACKGROUND: Anderson-Fabry disease (AFD) is an X-linked genetic disorder with deficient α-galactosidase A activity. The main aim of this work was to investigate possible differences in urine proteins between healthy controls and AFD patients and to identify abnormal proteins as potential biomarkers of disease. MATERIAL AND METHODS: We studied 2D electrophoresis images of urine samples collected from AFD patients and healthy subjects. The proteins were separated using isoelectric focusing method followed by SDS-PAGE. The proteins were then visualized by silver staining and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). RESULTS: We found out that the urinary spectra of all the Fabry disease samples included identical proteins with molecular weight around 20-40 kDa. The concentration of some proteins was more than three times higher in the AFD samples, compared to the controls. The abundant proteins were identified by MALDI-TOF MS and included the following: alpha-1-antitrypsin, alpha-1-microglobulin, prostaglandin H2 d-isomerase, complement-c1q tumor necrosis factor-related protein, and Ig kappa chain V-III. Possible glycosylation at Asn51 and Asn78 sites of the prostaglandin H2 d-isomerase was detected. CONCLUSIONS: AFD urinary proteomics revealed increased secretion of several proteins. We postulate that the observed difference in the amount of prostaglandin H2 d-isomerase and its position on two-dimensional gels might be related to different glycosylation in AFD subjects.
Assuntos
Doença de Fabry/urina , Proteoma/análise , Adolescente , Adulto , Idoso , Biomarcadores/urina , Eletroforese em Gel Bidimensional , Feminino , Glicosilação , Humanos , Oxirredutases Intramoleculares/urina , Focalização Isoelétrica , Lipocalinas/urina , Masculino , Pessoa de Meia-Idade , Peso Molecular , Proteínas/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto JovemRESUMO
The linear solvation energy relationship (LSER) model was used to characterize interactions responsible for sorption of volatile organic compounds (VOCs) in air samples on six different solid-phase microextraction (SPME) fibers at 296K and zero relative humidity. The polydimethylsiloxane and polyacrylate fibers sorption data were also modeled at different relative humidities in the range of 10-90% and influence of water vapors on the extraction process is discussed. The LSER equations were obtained by a multiple regression of the distribution coefficients of 14 probe solutes on an appropriate SPME fiber against the solvation parameters of the solutes. The derived LSER equations successfully predicted the VOC distribution coefficients and the selectivity of individual SPME fibers for the various volatile solutes. The LSER approach coupled with SPME is a relatively simple and reliable tool to rapidly characterize the sorption mechanism of VOCs with various stationary phases and may potentially be applied to design and test new chromatographic materials for sampling or separation of VOCs.
Assuntos
Ar/análise , Compostos Orgânicos/análise , Microextração em Fase Sólida/métodos , Adsorção , Umidade , Análise Multivariada , Compostos Orgânicos/isolamento & purificação , VolatilizaçãoRESUMO
A GC/MS procedure has been developed, optimized, and applied to characterization of oil binders in paintings. The procedure involves hydrolysis of lipids to fatty acids (FAs) and derivatization of FAs to fatty acid methyl esters (FAMEs) by a solution of sodium methanolate in methanol at an elevated temperature. FAMEs are analyzed by temperature-programed GC followed by full-scan MS. Old and dried samples are subjected to extraction of nonpolymerized FAMEs into dichloromethane prior to hydrolysis. The method provides a good repeatability of results and has been applied to the characterization of common plant oils used in paintings, to commercial oil and tempera paints, to model painting samples, and to samples taken from real paintings. The fresh oils and binders can readily be identified and characterized. The ratio of the methyl esters of palmitic and stearic acids can be used to characterize oil binders in old works of art.
RESUMO
Matriptase-2 (TMPRSS6) is an important negative regulator of hepcidin expression; however, the effects of iron overload or accelerated erythropoiesis on liver TMPRSS6 protein content in vivo are largely unknown. We determined TMPRSS6 protein content in plasma membrane-enriched fractions of liver homogenates by immunoblotting, using a commercial antibody raised against the catalytic domain of TMPRSS6. Plasma membrane-enriched fractions were obtained by centrifugation at 3000 g and washing. TMPRSS6 was detected in the 3000 g fraction as a 120 kDa full-length protein in both mice and rats. Feeding of iron-deficient diet as well as erythropoietin treatment increased TMPRSS6 protein content in rats and mice by a posttranscriptional mechanism; the increase in TMPRSS6 protein by erythropoietin was also observed in Bmp6-mutant mice. Administration of high doses of iron to mice (200, 350 and 700 mg/kg) decreased TMPRSS6 protein content. Hemojuvelin was detected in the plasma membrane-enriched fractions of control animals as a full length protein of approximately 52 kDa; in iron deficient animals, the full length protein was partially cleaved at the N-terminus, resulting in an additional weak band of approximately 47 kDa. In livers from hemojuvelin-mutant mice, TMPRSS6 protein content was strongly decreased, suggesting that intact hemojuvelin is necessary for stable TMPRSS6 expression in the membrane. Overall, the results demonstrate posttranscriptional regulation of liver TMPRSS6 protein by iron status and erythropoietin administration, and provide support for the interaction of TMPRSS6 and hemojuvelin proteins in vivo.
Assuntos
Eritropoetina/metabolismo , Deficiências de Ferro , Sobrecarga de Ferro/metabolismo , Ferro/metabolismo , Fígado/metabolismo , Proteínas de Membrana/metabolismo , Serina Endopeptidases/metabolismo , Anemia Ferropriva/metabolismo , Animais , Proteína Morfogenética Óssea 6/genética , Modelos Animais de Doenças , Eritropoetina/farmacologia , Feminino , Proteínas Ligadas por GPI , Proteína da Hemocromatose , Fígado/efeitos dos fármacos , Masculino , Camundongos , Camundongos Knockout , Mutação , Ratos , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
Magnetic bead cellulose was prepared by a suspension method from the mixture of viscose and magnetite using thermal sol-gel transition and regeneration of cellulose. The prepared magnetic particles after their activation with divinyl sulfone were shown to be suitable magnetic carrier for immobilization of α-chymotrypsin and for its application in proteomic studies. The specific activity of the immobilized proteinase was high; its activity did not change in the course of storage. The following properties of the immobilized proteinase were compared with those of the soluble enzyme: pH and temperature dependence of the activity, self-cleavage activity, and possibility of repeated use. α-Chymotrypsin immobilized to magnetic bead cellulose was used for the proteolytic digestion of porcine pepsin A and human gastric juice and a possibility of direct use of enzyme reaction products for matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis was shown.