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Purpose: The aim of the study was to analyse the usefulness of core biopsy in the diagnosis of malignant neoplasms of the pancreas - sensitivity and accuracy of diagnosis, safety of the procedure, indication of factors that may increase the risk of complications after biopsy. Material and methods: A retrospective analysis of data was performed in a group of 100 patients diagnosed with a focal lesion of the pancreas, qualified for a core biopsy. Results: The results are a sensitivity of 92%, a specificity of 100%, and an accuracy of 93.3%. The incidence of more severe complications according to the Clavien-Dindo classification was 1% (one case in the material studied). The results of the analysis were compared with the results of other authors, showing similar values for the sensitivity and specificity of the method and low rates of serious complications; it also seems that the tissue material obtained by core biopsy has higher diagnostic potential than that obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), currently considered the method of choice. In addition, the costs of transabdominal biopsy and endoscopic biopsy were compared; the lower cost of the former may be an important economic issue when choosing the biopsy method. Conclusions: The results show core biopsy to be a sensitive, accurate, and safe method for obtaining the tissue necessary to plan treatment in patients with pancreatic cancer.
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Irreversible electroporation (IRE) of locally advanced pancreatic cancer is an increasingly used method for unresectable pancreatic cancer that can be used in cytoreduction followed by surgical treatment and shows promising results in palliative care. IRE is an ablative technique where electric pulses cause damage to the cell membrane leading to apoptosis without the destruction of stroma. The application of IRE increases the concentration of hydrophobic regimens like bleomycin within the tumor, what could improve the effectiveness of treatment. This fusion of those two treatments is called electrochemotherapy. In this review, the authors will discuss the radiological perspective of possible beneficial role of irreversible electroporation in relation with chemotherapy in pancreatic cancer treatment.
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Autosomal dominant polycystic kidney disease (ADPKD) constitutes the fourth cause of end-stage renal disease in Europe. The course of the disease varies widely among patients with ADPKD. Due to the emergence of new possibilities of pharmacotherapy, it has become crucial to identify the group of patients with the fastest rate and risk of disease progression. This particular group of patients will benefit most from the therapy and they are the best candidates for clinical trials. At the early stages of ADPKD typical markers of severity and progression of the disease remain unchanged in contrast to the kidney volume, which increases continuously in an exponential way. Therefore, the use of height-adjusted total kidney volume as a biomarker should become a mandatory diagnostic option. Also, quantitative MRI techniques are promising biomarkers for the evaluation of disease severity and could provide additional insights into its course.
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BACKGROUND: There is evidence for neurosyphilis being associated with the central nervous system vasculitis involving medium and small vessels. As the hemispheric white matter is the major target of these vascular alterations the white matter axonal and myelination disruption may be observed employing measure for the rate of water molecule diffusion. High apparent diffusion coefficient (ADC) correspond to unimpeded water diffusion and indicating white matter disintegration. CASE REPORTS: In a retrospective study exploringcentral nervous system magnetic resonance (MR) images of two subjects presenting with neurosyphilis the ADC values were found to be increased as related to normal values being accompanied with normal appearing white matter of hemispheres. CONCLUSIONS: Applying ADC analysis to evaluate the brain in patients with neurosyphilis may reveal undetectable changes and explain the scale of abnormalities that occur in CNS. The increased mean ADC valuesin the normal appearing white matter of the hemispheres may correlate with neuropsychoatric symptomatology in syphilis.
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Neurossífilis , Substância Branca , Imagem de Difusão por Ressonância Magnética , Humanos , Neurossífilis/complicações , Neurossífilis/diagnóstico por imagem , Estudos Retrospectivos , Substância Branca/diagnóstico por imagem , Substância Branca/patologiaRESUMO
Aquaporins (AQPs), also known as water channel proteins, are members of a large protein family termed Major Intrinsic Proteins (MIP). The mammalian AQPs have been most comprehensively described, while knowledge about AQPs in invertebrates is limited mainly to insects. Not a single AQP protein has been described in snails to date. Consequently, we decided to search for the proteins in gastropod representatives, namely Lymnaea stagnalis, Catascopia occulta, and Stagnicola palustris (Mollusca; Gastropoda; Pulmonata; Lymnaeidae). Using the molecular approach, we identified L. stagnalis, C. occulta, and S. palustris open reading frames (ORFs) showing homology to AQP genes available in GenBank database, and characterized the encoded proteins, referred to as LsAQP1, CoAQP1, and SpAQP1, respectively. The putative snail aquaporins contain 299 amino acids, have a molecular mass of about 32 kDa, display the general AQP topology and three-dimensional structure congruent with orthodox AQPs, i.e., water-specific ones. Due to high levels of similarity in their characteristics, LsAQP1 was chosen for further studies, as the obtained results were supposed to be applicable for CoAQP1 and SpAQP1. Expression analysis revealed the presence of LsAQP1 transcript in the digestive tract, the cerebral ganglia, the kidney, the reproductive system, and the foot, suggesting that LsAQP1 as well as CoAQP1 and SpAQP1 are ubiquitous proteins and may play important roles in many essential water transport processes. The role appears to be confirmed by results of the yeast growth complementation assay pointing at functionality of LsAQP1. Thus, the obtained results support the AQP expression in gastropod tissues for the first time.
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Aquaporinas/genética , Caramujos/genética , Sequência de Aminoácidos , Animais , Aquaporinas/química , Sequência de Bases , Regulação da Expressão Gênica , Interações Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Dados de Sequência Molecular , Fases de Leitura Aberta , Especificidade de Órgãos/genética , Filogenia , Conformação Proteica , Alinhamento de Sequência , Caramujos/classificaçãoRESUMO
PURPOSE: The study aims at assessing the quantitative features which distinguish focal liver lesions (FLLs) in gadoxetic acid (GA) enhanced liver MRI and at determining whether these features can accurately differentiate benign from malignant lesions. MATERIAL AND METHODS: 107 patients with 180 unequivocal FLLs in previous examinations were included in a single-center retrospective study. All patients underwent a MRI test of the liver with GA. 99 benign and 74 malignant lesions were included. The group of benign lesions consisted of 60 focal nodular hyperplasias (FNH), 22 hemangiomas (HMG), 6 hepatic adenomas (HA), and 11 other benign lesions (1 angiomyolipioma, 6 lesions histopathology diagnoses as benign without further specification, or ones lacking features of malignancy, and 4 lesions radiologically diagnosed as benign which remained stable in the follow-up studies). The group of malignant lesions consisted of primary 51 hepatocellular carcinomas, 12 metastases, and 11 metastases from melanoma malignum (MM meta). 7 FLLs were excluded (4 cases of uncertain histopathological diagnosis, 2 cholangiocarcinomas, and 1 regenerative nodule). For the included lesions ROI (region of interest) measurements were taken by two observers in the T2-w, ADC (apparent diffusion coefficient) and in the T1-w sequence in the hepatobiliary phase (HBP). The interobserver agreement was evaluated with the Wilcoxon test. The Kruskal - Wallis, Mann - Whitney U and post hoc Dunn's tests were applied to assess if there were any significant differences in the ROI values between individual lesions. The variables with the p values of < 0.05 were considered statistically significant. RESULTS: We found significant differences in the ROI values between lesions with p < 0.0001. Strikingly high ROI values in the T2-w sequence were found for HMG. The lowest ADC values were encountered for metastases and MM metastases. The highest ROI values in the HBP were found for FNH, and the lowest for metastases. We also found statistically significant differences in the ROI values between benign and malignant lesions with benign lesions presenting statistically higher ROI values compared to malignant lesions. CONCLUSIONS: There were significant differences in the ROI values among different types of FLLs. The predominant quantitative feature in the T2-w sequence was a strikingly high ROI value for HMG. Benign lesions presented statistically higher ROI values in the T2-w, ADC, and HBP sequences compared to malignant lesions. This was true for all lesions except for HA.
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Adenoma de Células Hepáticas , Hiperplasia Nodular Focal do Fígado , Gadolínio DTPA , Hemangioma , Neoplasias Hepáticas , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Estudos Retrospectivos , Sensibilidade e Especificidade , Imageamento por Ressonância Magnética , Imagem de Difusão por Ressonância Magnética , Hemangioma/diagnóstico por imagem , Diagnóstico Diferencial , Meios de ContrasteRESUMO
Features of shell and genitalia as well as nucleotide sequences of selected mitochondrial and nuclear genes of specimens of Monachacantiana from ten northern French and two Dutch populations were compared with the same features of British and Italian populations. They were found to be very similar to populations previously identified as belonging to the CAN-1 lineage of M.cantiana. This confirms previous suggestions that M.cantiana was introduced to western Europe (England, France and the Netherlands) in historical times.
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Plant S1-like nucleases, often referred to as nuclease I enzymes, are the main class of enzymes involved in nucleic acid degradation during plant programmed cell death. The catalytically active site of these enzymes shows a significant similarity to the well-described P1 nuclease from Penicillium citrinum. Previously published studies reported that plant S1-like nucleases possess catalytic activities similar to their fungal orthologs, i.e. they hydrolyze single-stranded DNA and RNA, and less efficiently double-stranded DNA, in the presence of zinc ions. Here we describe a comprehensive study of the nucleolytic activities of all Arabidopsis S1-like paralogs. Our results revealed that different members of this family are characterized by a surprisingly large variety of catalytic properties. We found that, in addition to Zn(2+)-dependent enzymes, this family also comprises nucleases activated by Ca(2+) and Mn(2+), which implies that the apparently well-known S1 nuclease active site in plant nucleases is able to cooperate with different activatory ions. Moreover, particular members of this class differ in their optimum pH value and substrate specificity. These results shed new light on the widely accepted classification of plant nucleases which is based on the assumption that the catalytic requirements of plant nucleases reflect their phylogenetic origin. Our results imply the need to redefine the understanding of the term 'nuclease I'. Analysis of the phylogenetic relationships between S1-like enzymes shows that plant representatives of this family evolve toward an increase in catalytic diversity. The importance of this process for the biological functions of plant S1-type enzymes is discussed.
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Proteínas de Arabidopsis/genética , Arabidopsis/genética , Endonucleases/genética , Evolução Molecular , Sequência de Aminoácidos , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Biocatálise/efeitos dos fármacos , Western Blotting , Cálcio/farmacologia , Domínio Catalítico , DNA de Cadeia Simples/metabolismo , Endonucleases/química , Endonucleases/classificação , Endonucleases/metabolismo , Concentração de Íons de Hidrogênio , Isoenzimas/classificação , Isoenzimas/genética , Isoenzimas/metabolismo , Manganês/farmacologia , Modelos Moleculares , Dados de Sequência Molecular , Filogenia , RNA/metabolismo , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Zinco/farmacologiaRESUMO
COVID-19 infection is associated with myocarditis, and cardiovascular magnetic resonance (CMR) is the reference non-invasive imaging modality for myocardial tissue characterization. Quantitative CMR techniques, such as feature tracking (FT) and left ventricular global longitudinal strain (GLS) analysis, have been introduced as promising diagnostic tools to improve the diagnostic accuracy of suspected myocarditis. The aim of this study was to analyze the left ventricular global longitudinal strain (GLS) and the influence of T1 and T2 relaxation times, ECV, and LGE appearance on GLS parameters in a multiparametric imaging protocol in patients who recovered from COVID-19. The 86 consecutive patients enrolled in the study had all recovered from mild or moderate COVID-19 infections; none required hospitalization. Their persistent symptoms and suspected myocarditis led to cardiac magnetic resonance imaging within 3 months of the diagnosis of the SARS-CoV-2 infection. Results: Patients with GLS less negative than -15% had significantly lower LVEF (53.6% ± 8.9 vs. 61.6% ± 4.8; <0.001) and were significantly more likely to have prolonged T1 (28.6% vs. 7.5%; p = 0.019). Left ventricular GLS correlated significantly with T1 (r = 0.303; p = 0.006) and LVEF (r = -0.732; p < 0.001). Left ventricular GLS less negative than -15% was 7.5 times more likely in patients with prolonged T1 (HR 7.62; 95% CI 1.25-46.64). The reduced basal inferolateral longitudinal strain had a significant impact on the global left ventricular longitudinal strain. ROC results suggested that a GLS of 14.5% predicted prolonged T1 relaxation time with the best sensitivity and specificity. Conclusions: CMR abnormalities, including a myocarditis pattern, are common in patients who have recovered from COVID-19. The CMR feature-tracking left ventricular GLS is related to T1 relaxation time and may serve as a novel parameter to detect global and regional myocardial injury and dysfunction in patients with suspected myocardial involvement after recovery from COVID-19.
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The mitochondrial genome of Monachacartusiana is the first complete mitochondrial sequence described for the pulmonate snail genus Monacha and for the family Hygromiidae. The identified mitogenome has a length of 13,894 bp and encodes 13 proteins, 22 tRNAs, and two rRNAs. A phylogenetic analysis of available mitogenomes from representatives of helicoid families shows a sister group relationship of Hygromiidae and Geomitridae, which have been recently recognised as separate families.
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Introduction: We hypothesized that, based on magnetic resonance enterography (MRE) and the apparent diffusion coefficient (ADC), measured in the affected parts of the intestine, it is possible to effectively differentiate active and chronic phases of Crohn's disease. Aim: To create a multidimensional diagnostic model for differentiating between the phases of Crohn's disease. Material and methods: This study included 125 patients - 55 women (aged 19 to 66 years) and 70 men (aged 12 to 67 years) - who underwent MRE and ADC measurement for the first time. Results: The group of potential explanatory variables comprised 11 variables, including the thickness and length of the occupied section, number of lymph nodes, layered bowel wall enhancement, total transitions on fat tissue, and features of restricted diffusion. The final discrimination model was based on 2 variables: ADC (A) and layered bowel wall enhancement (W). Active Crohn's disease was defined as -6.339 + 4.747 × W + 0.008 × A, while chronic Crohn's disease was defined as -11.365 + 2.812 × W + 0.012 × A. Definitive diagnosis was based on histological examination of material collected during ileocolonoscopy in 96 patients, surgery with subsequent histopathological examination in 17 patients, and capsule endoscopy in 12 patients. Conclusions: The predictive model described here could identify the active form of Crohn's disease with a probability of 93.06% and the chronic form with a probability of 75.57%. The use of classic MRE layered bowel wall enhancement and a DWI-based ADC metric eliminates the main shortcomings of both approaches.
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BACKGROUND: Radiological imaging methods used at a large scale in the assessment of hepatic lesions include: Ultrasound, computed tomography and magnetic resonance. To further characterize these lesions, specific contrast agents may be added, thus revealing the vascularity of the lesions. DISCUSSION: This review focuses on gadoxetic acid, which is a hepatospecific contrast agent used in MRI. The aim of the review is to briefly explain the mechanism of GA enhancement, describe the enhancement patterns of some benign and malignant hepatic lesions and discuss possible advantages of GA over standard contrast agents. CONCLUSION: The role of GA in functional MR cholangiography and the idea of accessing liver function by measuring parenchymal enhancement will also be explained.
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Meios de Contraste , Gadolínio DTPA , Aumento da Imagem/métodos , Neoplasias Hepáticas/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Humanos , Fígado/diagnóstico por imagemRESUMO
The widespread presence of overweight and obesity increases with every decade, and the number of people with body mass index (BMI) >30 kg/m2 has doubled in the last 30 years. The aim of the study is to assess the correlation between MRI-evaluated ectopic fat accumulation in pancreas, skeletal muscles and liver and the incidence of type 2 diabetes and hypertension, depending on BMI and waist circumference ratio. This prospective study included 267 consecutive patients who were referred to abdominal MRI and underwent a standard clinical assessment with BMI and waist circumference ratio calculation. Ectopic fat accumulation in pancreas, skeletal muscles and liver was evaluated in magnetic resonance imaging using the fat-water separated Dixon imaging. There were statistically significant differences in mean steatosis of all assessed organs in the group of patients with type 2 diabetes or hypertension in comparison to the non-diabetic group as well as to the group without hypertension. It has been observed that pancreas and skeletal muscles are more susceptible to fat accumulation than liver. According to our results, there is a relation between the fat content in muscles, pancreas and liver, the incidence of type 2 diabetes and hypertension and also body mass index and waist circumference ratio. We believe that future studies should aim to determine whether the use of fat content measurement in certain organs could be used as a biomarker that can enable early detection of reversible metabolic changes, as well as their subsequent monitoring.
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Tecido Adiposo/diagnóstico por imagem , Diabetes Mellitus Tipo 2/epidemiologia , Hipertensão/epidemiologia , Fígado/diagnóstico por imagem , Músculo Esquelético/diagnóstico por imagem , Pâncreas/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Humanos , Incidência , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , Pâncreas/metabolismo , Estudos Prospectivos , Circunferência da Cintura , Adulto JovemRESUMO
Specimens obtained from ten populations of a Monacha species from the central Apennines were compared with six molecular lineages of Monacha cantiana s. l. (CAN-1, CAN-2, CAN-3, CAN-4, CAN-5, CAN-6) and two other Monacha species (M. cartusiana and M. parumcincta), treated as outgroup, by molecular (nucleotide sequences of two mitochondrial COI and 16S rDNA as well as two nuclear ITS2 and H3 gene fragments) and morphological (shell and genital anatomy) analysis. The results strongly suggest that these populations represent a separate species for which two names are available: the older Helix pantanellii De Stefani, 1879 and the junior M. ruffoi Giusti, 1973. The nucleotide sequences created well separated clades on each phylogenetic tree. Genital anatomy included several distinctive features concerning vaginal appendix, penis, penial papilla and flagellum; instead, shell characters only enabled them to be distinguished from M. cartusiana and M. parumcincta. Remarkably, populations of M. pantanellii show high morphological variability. Shell variability mainly concerns size, some populations having very small dimensions. Genital variability shows a more intricate pattern of all anatomical parts, being higher as regards the vagina and vaginal appendix. Despite this morphological variability, the K2P distance range of COI sequences between populations is narrow (0.2-4.5%), if we consider all but three of the 53 sequences obtained. This research confirmed that the species of Monacha and their molecularly distinguished lineages can only occasionally be recognised morphologically and that they have significant inter- and intra-population variability. The possibility of using an overall approach, including shell, genital and molecular evidence, was taken in order to establish a reliable taxonomic setting.
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Two new lineages CAN-5 and CAN-6 were recognised in four populations of Monachacantiana (Montagu, 1803) s.l. from the Italian Apuan Alps by joint molecular and morphological analysis. They are different from other M.cantiana lineages known from English, Italian, Austrian and French populations, i.e. CAN-1, CAN-2, CAN-3 and CAN-4, as well as from the other Italian Monacha species used for comparisons (M.parumcincta and M.cartusiana). Although a definite taxonomic and nomenclatural setting seems to be premature, we suggest that the name or names for these new lineages as one or two species should be found among 19th century names (Helixsobara Mabille, 1881, H.ardesa Mabille, 1881, H.apuanica Mabille, 1881, H.carfaniensis De Stefani, 1883 and H.spallanzanii De Stefani, 1884).
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Purpose: Obesity, defined as a body mass index (BMI) exceeding 30 kg/m2, is a serious health problem, which can be called an epidemic on a global scale and is one of the most important causes of preventable death. The aim of this study was to assess ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with metabolic syndrome (MetS). Patients and methods: The study included 267 consecutive patients who underwent a standard clinical assessment with BMI calculation. Ectopic fat accumulation in pancreas, liver, and skeletal muscle was evaluated by magnetic resonance imaging (MRI) using fat-water separated Dixon imaging. MetS was defined according to the criteria modified by the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Central obesity was defined using gender and ethnic-specific values for waist circumference. Results: There was a statistically significant correlation between the degree of steatosis of the assessed organs and BMI value as well as waist circumference ratio, that determined the degree of central obesity. It was found that the most rapid relative fat accumulation was in muscle, then in pancreas and then in liver. Higher steatosis of pancreas, liver, and muscle was demonstrated depending on the number of the satisfied MetS criteria. Conclusion: Knowing that pancreatic fatty disease is a risk factor for MetS, it seems that assessment and monitoring of ectopic fat accumulation may have important clinical implications and may be used in the prediction of metabolic risk and its early prevention.
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BACKGROUND: The aim of the study was to evaluate the prognostic properties of perfusion parameters of liver parenchyma based on computed tomography (CT) of patients with acute pancreatitis (AP) made on the first day of onset of symptoms, to assess their usefulness in identifying patients with increased risk of the development of severe AP. METHODS: 79 patients with clinical symptoms and biochemical criteria indicative of AP underwent perfusion computed tomography (p-CT) within 24 hours after onset of the symptoms. Perfusion parameters in 41 people who developed a severe form of AP were compared with parameters in 38 patients in whom the course of AP was mild. RESULTS: Statistical differences in the liver perfusion parameters between the group of patients with mild and severe AP were shown. The permeability-surface area product was significantly lower, and the hepatic arterial fraction was significantly higher in the group of patients with progression of AP. CONCLUSIONS: Based on the results, it seems that p-CT performed on the first day from the onset of AP is a method that, by revealing disturbances in hepatic perfusion, can help in identifying patients with increased risk of the development of severe AP.
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The purpose of this study was establishing the basic energetic parameters of amoeba Acanthamoeba castellanii mitochondria respiring with malate and their response to oxidative stress caused by hydrogen peroxide in the presence of Fe(2+) ions. It appeared that, contrary to a previous report (Trocha LK, Stobienia O (2007) Acta Biochim Polon 54: 797), H(2)O(2)-treated mitochondria of A. castellanii did not display any substantial impairment. No marked changes in cytochrome pathway activity were found, as in the presence of an inhibitor of alternative oxidase no effects were observed on the rates of uncoupled and phosphorylating respiration and on coupling parameters. Only in the absence of the alternative oxidase inhibitor, non-phosphorylating respiration progressively decreased with increasing concentration of H(2)O(2), while the coupling parameters (respiratory control ratio and ADP/O ratio) slightly improved, which may indicate some inactivation of the alternative oxidase. Moreover, our results show no change in membrane potential, Ca(2+) uptake and accumulation ability, mitochondrial outer membrane integrity and cytochrome c release for 0.5-25 mM H(2)O(2)-treated versus control (H(2)O(2)-untreated) mitochondria. These results indicate that short (5 min) incubation of A. castellanii mitochondria with H(2)O(2) in the presence of Fe(2+) does not damage their basic energetics.
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Acanthamoeba castellanii/metabolismo , Acanthamoeba castellanii/efeitos dos fármacos , Animais , Cálcio/metabolismo , Citocromos c/metabolismo , Metabolismo Energético/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Transporte de Íons/efeitos dos fármacos , Malatos/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacosRESUMO
We identified a human orthologue of tRNA:m5C methyltransferase from Saccharomyces cerevisiae, which has been previously shown to catalyse the specific modification of C34 in the intron-containing yeast pre-tRNA Leu (CAA). Using transcripts of intron-less and intron-containing human pre-tRNA Leu (CAA) genes as substrates, we have shown that m5C34 is introduced only in the intron-containing tRNA precursors when the substrates were incubated in the HeLa extract. m5C34 formation depends on the nucleotide sequence surrounding the wobble cytidine and on the structure of the prolongated anticodon stem. Expression of the human Trm4 (hTrm4) cDNA in yeast partially complements the lack of the endogenous Trm4p enzyme. The yeast extract prepared from the strain deprived of the endogenous TRM4 gene and transformed with hTrm4 cDNA exhibits the same activity and substrate specificity toward human pre-tRNALeu transcripts as the HeLa extract. The hTrm4 MTase has a much narrower specificity against the yeast substrates than its yeast orthologue: human enzyme is not able to form m5C at positions 48 and 49 of human and yeast tRNA precursors. To our knowledge, this is the first report showing intron-dependent methylation of humanpre-tRNA Leu (CAA) and identification of human gene encoding tRNA methylase responsible for this reaction.
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5-Metilcitosina/metabolismo , Anticódon/metabolismo , Metiltransferases/metabolismo , Precursores de RNA/química , Precursores de RNA/metabolismo , RNA de Transferência de Leucina/química , RNA de Transferência de Leucina/metabolismo , tRNA Metiltransferases/metabolismo , Anticódon/química , Sequência de Bases , Catálise , Células HeLa , Humanos , Íntrons , Metiltransferases/química , Metiltransferases/genética , Dados de Sequência Molecular , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato , tRNA Metiltransferases/química , tRNA Metiltransferases/genéticaRESUMO
Molecular analysis of nucleotide sequences of mitochondrial cytochrome oxidase subunit 1 (COI) and 16S ribosomal DNA (16SrDNA) as well as nuclear histone 3 (H3) and internal transcribed spacer 2 of rDNA (ITS2) gene fragments together with morphological analysis of shell and genitalia features showed that English, French and Italian populations usually assigned to Monacha cantiana consist of four distinct lineages (CAN-1, CAN-2, CAN-3, CAN-4). One of these lineages (CAN-1) included most of the UK (five sites) and Italian (five sites) populations examined. Three other lineages represented populations from two sites in northern Italy (CAN-2), three sites in northern Italy and Austria (CAN-3), and two sites in south-eastern France (CAN-4). The taxonomic and nomenclatural setting is only currently available for lineages CAN-1 and CAN-4; a definitive frame for the other two requires much more research. The lineage CAN-1 corresponds to the true M. cantiana (Montagu, 1803) because it is the only one that includes topotypical English populations. The relationships and genetic distances support the hypothesis of the Italian origin of this lineage which was probably introduced to England by the Romans. The lineage CAN-4 is attributed to M. cemenelea (Risso, 1826), for which a neotype has been designated and deposited. Its diagnostic sequences of COI, 16SrDNA, H3 and ITS2 genes have also been deposited in GenBank. Molecular and morphological (shell and genitalia) features showed that M. parumcincta (Rossmässler, 1834) is a distinct taxon from the M. cantiana lineages.