RESUMO
OBJECTIVES: To assess the effect of iodine attenuation on pulmonary nodule volumetry using virtual non-contrast (VNC) and mono-energetic reconstructions. METHODS: A consecutive series of patients who underwent a contrast-enhanced chest CT scan were included. Images were acquired on a novel dual-layer spectral CT system. Conventional reconstructions as well as VNC and mono-energetic images at different keV levels were used for nodule volumetry. RESULTS: Twenty-four patients with a total of 63 nodules were included. Conventional reconstructions showed a median (interquartile range) volume and diameter of 174 (87 - 253) mm3 and 6.9 (5.4 - 9.9) mm, respectively. VNC reconstructions resulted in a significant volume reduction of 5.5% (2.6 - 11.2%; p<0.001). Mono-energetic reconstructions showed a correlation between nodule attenuation and nodule volume (Spearman correlation 0.77, (0.49 - 0.94)). Lowering the keV resulted in increased volumes while higher keV levels resulted in decreased pulmonary nodule volumes compared to conventional CT. CONCLUSIONS: Novel dual-layer spectral CT offers the possibility to reconstruct VNC and mono-energetic images. Those reconstructions show that higher pulmonary nodule attenuation results in larger nodule volumes. This may explain the reported underestimation in nodule volume on non-contrast enhanced compared to contrast-enhanced acquisitions. KEY POINTS: ⢠Pulmonary nodule volumes were measured on virtual non-contrast and mono-energetic reconstructions ⢠Mono-energetic reconstructions showed that higher attenuation results in larger volumes ⢠This may explain the reported nodule volume underestimation on non-contrast enhanced CT ⢠Mostly metastatic pulmonary nodules were evaluated, results might differ for benign nodules.
Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Iodo/farmacologia , Neoplasias Pulmonares/diagnóstico , Nódulos Pulmonares Múltiplos/diagnóstico , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Idoso , Meios de Contraste/farmacologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Curva ROCRESUMO
Schwannomas are benign Schwann cell-derived tumors of the peripheral nerve sheath often involving the vestibular cranial nerve (vestibular schwannoma). Histologically, they consist of bipolar spindle cells and show a moderate cellularity. Typically, Antoni A regions with a storiform pattern and loose Antoni B regions are intermingled. Verocay bodies are the pathognomonic palisading structures. Malignant transformation is rare. Merlin (schwannomin), the protein product of NF2, is inactivated by mutations, loss of heterozygosity or methylation. Within neurofibromatosis type 2, a germline mutation is present in about half of cases, whereas tumors demonstrate an additional second hit of the NF2 gene. A loss of chromosome 22 or 22q is common. Merlin links the cell membrane with the cytoskeleton and regulates intracellular signaling pathways leading to dysorganization when merlin is inactivated. Loss of merlin activates Rac1 and Ras, and the PAK1, mTORC1, EGFR-Ras-ERK, PI3K-Akt, WNT and Hippo pathways as well as receptor tyrosine kinases. Furthermore, merlin locates to the nucleus and inhibits E3 ubiquitin ligase CRL4DCAF1. Besides biallelic inactivation of NF2 in schwannomas, other genes are involved in the pathogenesis of schwannomatosis-associated schwannomas such as LZTR1, SMARCB1, COQ6 indicating an important role of SWI/SNF chromatin-remodeling complex for schwannoma development. Our own investigations point to deregulation of BAF170, another essential SWI/SNF complex component. Knowledge of mechanisms allows targeted molecular therapy, especially in vestibular schwannomas, using antagonists against mTOR (rapamycin/sirolmus/everolimus), EGFR (lapatinib) or VEGF (bevacizumab), although clinical studies have been in part disappointing so far.
Assuntos
Biomarcadores Tumorais/metabolismo , Neurofibromatose 2/metabolismo , Neurofibromina 2/metabolismo , Neuroma Acústico/metabolismo , Neuroma Acústico/patologia , Regulação Neoplásica da Expressão Gênica , HumanosRESUMO
Until recently, cardiovascular computed tomography angiography (CCTA) was associated with considerable radiation doses. The introduction of tube current modulation and automatic tube potential selection as well as high-pitch prospective ECG-triggering and iterative reconstruction offer the ability to decrease dose with approximately one order of magnitude, often to sub-millisievert dose levels. In parallel, advancements in computational technology have enabled the measurement of fractional flow reserve (FFR) from CCTA data (FFRCT). This technique shows potential to replace invasively measured FFR to select patients in need of coronary intervention. Furthermore, developments in scanner hardware have led to the introduction of dual-energy and photon-counting CT, which offer the possibility of material decomposition imaging. Dual-energy CT reduces beam hardening, which enables CCTA in patients with a high calcium burden and more robust myocardial CT perfusion imaging. Future-generation CT systems will be capable of counting individual X-ray photons. Photon-counting CT is promising and may result in a substantial further radiation dose reduction, vastly increased spatial resolution, and the introduction of a whole new class of contrast agents.
Assuntos
Técnicas de Imagem de Sincronização Cardíaca/métodos , Angiografia por Tomografia Computadorizada/métodos , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Exposição à Radiação/prevenção & controle , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Humanos , Doses de Radiação , Proteção Radiológica/métodos , Intensificação de Imagem Radiográfica/métodosRESUMO
BACKGROUND AND PURPOSE: Carotid siphon calcification might contribute to the high prevalence of cerebrovascular disease in pseudoxanthoma elasticum through increased arterial flow pulsatility. This study aimed to compare intracranial artery flow pulsatility, brain volumes, and small-vessel disease markers between patients with pseudoxanthoma elasticum and controls and the association between arterial calcification and pulsatility in pseudoxanthoma elasticum. MATERIALS AND METHODS: Fifty patients with pseudoxanthoma elasticum and 40 age- and sex-matched controls underwent 3T MR imaging, including 2D phase-contrast acquisitions for flow pulsatility in the assessment of ICA and MCA and FLAIR acquisitions for brain volumes, white matter lesions, and infarctions. All patients with pseudoxanthoma elasticum underwent CT scanning to measure siphon calcification. Flow pulsatility (2D phase-contrast), brain volumes, white matter lesions, and infarctions (3D T1 and 3D T2 FLAIR) were compared between patients and controls. The association between siphon calcification and pulsatility in pseudoxanthoma elasticum was tested with linear regression models. RESULTS: Patients with pseudoxanthoma elasticum (mean age, 57 [SD, 12] years; 24 men) had significantly higher pulsatility indexes (1.05; range, 0.94-1.21 versus 0.94; range, 0.82-1.04; P = .02), lower mean GM volumes (597 [SD, 53] mL versus 632 [SD, 53] mL; P < .01), more white matter lesions (2.6; range, 0.5-7.5 versus 1.1; range, 0.5-2.4) mL; P = .05), and more lacunar infarctions (64 versus 8, P = .04) than controls (mean age, 58 [SD, 11] years; 20 men). Carotid siphon calcification was associated with higher pulsatility indexes in patients with pseudoxanthoma elasticum (ß = 0.10; 95% CI, 0.01-0.18). CONCLUSIONS: Patients with pseudoxanthoma elasticum have increased intracranial artery flow pulsatility and measures of small-vessel disease. Carotid siphon calcification might underlie the high prevalence of cerebrovascular disease in pseudoxanthoma elasticum.
Assuntos
Lesões Encefálicas , Calcinose , Transtornos Cerebrovasculares , Pseudoxantoma Elástico , Masculino , Humanos , Pessoa de Meia-Idade , Pseudoxantoma Elástico/complicações , Pseudoxantoma Elástico/diagnóstico por imagem , Pseudoxantoma Elástico/patologia , Artéria Carótida Interna/patologia , Transtornos Cerebrovasculares/diagnóstico por imagem , Transtornos Cerebrovasculares/complicações , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , InfartoRESUMO
BACKGROUND: The global prevalence of diabetes mellitus (DM) has been increasing over recent decades. In Germany, the prevalence for DM type 1 and type 2 in adults is estimated at about 7.7%. Hence, diabetes has to be classified as a serious public health concern. Being diagnosed with DM and facing possible sequelae might have a negative impact on patients' mental and physical well-being. However, diabetes not only affects patients themselves, but also their close relatives. To improve the quality of life for patients and relatives alike, the German Association of Diabetes Nurses and Education experts (VDBD) elaborated the first education program tailor-made for relatives of diabetes patients. This article describes the concept and design of the trial evaluating the efficacy of this education program called "DiaLife-Living Together with Diabetes". METHODS: This evaluation study is a cluster randomized controlled trial, in which the study centers will be randomly assigned either to the intervention group or the control group. Study centers will recruit relatives of and patients with DM type 1 and type 2. Members of the intervention group will participate in the education program DiaLife, whereas participants randomized in the control group will act as waiting-list controls. The study will assess the efficacy of DiaLife by comparing diabetes-related knowledge between the intervention and control groups as the primary outcome for participants. As the primary outcome in patients, the Hba1c value will be assessed. In addition, diabetes-related distress, family interaction, and other secondary endpoints will be considered as secondary outcomes. Long-term efficacy will be assessed 6 and 12 months after intervention. Hierarchical regression models will be used to analyze effects over time. DISCUSSION: While there is scientific evidence for the efficacy of education programs addressed to (diabetes) patients, there is a research gap with regard to intervention studies evaluating the efficacy of education programs designed for patients' relatives. The study results will provide information on the efficacy of the DiaLife education program. In addition, factors that might hinder a successful implementation of an education program for relatives will be identified. TRIAL REGISTRATION: German Clinical Trials Register, DRKS00015157 . Registered on 24 August 2018.
Assuntos
Diabetes Mellitus Tipo 1/terapia , Diabetes Mellitus Tipo 2/terapia , Família/psicologia , Educação em Saúde/métodos , Conhecimentos, Atitudes e Prática em Saúde , Adaptação Psicológica , Biomarcadores/sangue , Efeitos Psicossociais da Doença , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/psicologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/psicologia , Relações Familiares , Alemanha , Hemoglobinas Glicadas/metabolismo , Humanos , Estudos Multicêntricos como Assunto , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de TempoRESUMO
OBJECTIVES: To determine whether mild stage chronic obstructive pulmonary disease (COPD) can be detected on chest radiography without substantial overdiagnosis. METHODS: A retrospective nested case-control study (case:control, 1:1) was performed in 783 patients scheduled for cardiothoracic surgery who underwent both spirometry and a chest radiograph preoperative. Diagnostic accuracy of chest radiography for diagnosing mild COPD was investigated using objective measurements and overall appearance specific for COPD on chest radiography. Inter-observer variability was investigated and variables with a kappa >0.40 as well as baseline characteristics were used to make a diagnostic model which was aimed at achieving a high positive predictive value (PPV). RESULTS: Twenty percent (155/783) had COPD. The PPV of overall appearance specific for COPD alone was low (37-55%). Factors in the diagnostic model were age, type of surgery, gender, distance of the right diaphragm apex to the first rib, retrosternal space, sternodiaphragmatic angle, maximum height right diaphragm (lateral view) and subjective impression of COPD (using both views). The model resulted in a PPV of 100%, negative predictive value (NPV) of 82%, sensitivity of 10% and specificity of 100% with an area under the curve of 0.811. CONCLUSIONS: Detection of mild COPD without substantial overdiagnosis was not feasible on chest radiographs in our cohort.
Assuntos
Doença Pulmonar Obstrutiva Crônica/diagnóstico por imagem , Idoso , Estudos de Casos e Controles , Diafragma/fisiopatologia , Feminino , Volume Expiratório Forçado/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Radiografia Torácica/normas , Estudos Retrospectivos , Sensibilidade e Especificidade , Capacidade Vital/fisiologiaRESUMO
BACKGROUND: Complications might occur after great vessel stent implantation in children. Therefore follow-up using imaging is warranted. PURPOSE: To determine the optimal imaging modality for the assessment of stents used to treat great vessel obstructions in children. MATERIAL AND METHODS: Five different large vessel stents were evaluated in an in-vitro setting. All stents were expanded to the maximal vendor recommended diameter (20mm; n = 4 or 10mm; n = 1), placed in an anthropomorphic chest phantom and imaged with a 256-slice CT-scanner. MRI images were acquired at 1.5T using a multi-slice T2-weighted turbo spin echo, an RF-spoiled three-dimensional T1-weighted Fast Field Echo and a balanced turbo field echo 3D sequence. Two blinded observers assessed stent lumen visibility (measured diameter/true diameter *100%) in the center and at the outlets of the stent. Reproducibility of diameter measurements was evaluated using the intraclass correlation coefficient for reliability and 95% limits of agreement for agreement analysis. RESULTS: Median stent lumen visibility was 88 (IQR 86-90)% with CT for all stents at both the center and outlets. With MRI, the T2-weighted turbo spin echo sequence was preferred which resulted in 82 (78-84%) stent lumen visibility. Interobserver reliability and agreement was good for both CT (ICC 0.997, mean difference -0.51 [-1.07-0.05] mm) and MRI measurements (ICC 0.951, mean difference -0.05 [-2.52 --2.41] mm). CONCLUSION: Good in-stent lumen visibility was achievable in this in-vitro study with both CT and MRI in different great vessel stents. Overall reliability was good with clinical acceptable limits of agreement for both CT and MRI. However, common conditions such as in-stent stenosis and associated aneurysms were not tested in this in-vitro study, limiting the value of the in-vitro study.
Assuntos
Vasos Sanguíneos/diagnóstico por imagem , Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Stents , Tomografia Computadorizada por Raios X/métodos , Criança , Humanos , Variações Dependentes do Observador , Reprodutibilidade dos TestesRESUMO
Protein profiling is a promising tool for tumor characterization and the detection of tumor markers in bladder cancer. Techniques for 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and surface-enhanced laser desorption/ionization with time-of-flight mass spectrometry (SELDI-TOF-MS) have improved; both were evaluated using bladder tumor tissue. Normal urothelium and pTa G2, pT1 G3, and >or=pT3 G3 tissues were obtained from the operating room and, after macrodissection, subjected to 2D-PAGE and to SELDI-TOF-MS ProteinChip. 2D-PAGE gels expressed significantly different protein patterns for pTa G2 and pT3 G3 tumors. pT1 G3 tumors showed expression profiles similar to those of the invasive tumors, with upregulation of galectin 3, gelsolin, villin 2, moesin, and annexin 6. Similarly, distinct protein peaks were detected for superficial and muscle-invasive urothelial cancers by SELDI-TOF-MS. Six of seven superficial pTa G2 tumors showed an intense peak at 6.7 and 10.1 kD, while invasive carcinomas showed an intense peak near 9.5 kD. No disturbing influence of surrounding tissue on the results was detected. It was shown that both techniques (2D-PAGE and ProteinChip) work well, and especially ProteinChip analysis seems promising for clinical application.
Assuntos
Análise Serial de Proteínas , Neoplasias da Bexiga Urinária/diagnóstico , Biomarcadores Tumorais , Eletroforese em Gel Bidimensional , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Neoplasias da Bexiga Urinária/metabolismoRESUMO
Different life cycle stages of Haemonchus contortus adapt to different ecosystems. This adaptation is accompanied by alterations in gene transcription and expression associated with the energy, amino acid, nitrogen, lipid and/or nucleic acid metabolism of the respective stages. For example, the aerobic metabolism of larvae depends on an efficient citric acid cycle, whereas the anaerobic metabolism of adults requires glycolysis, resulting in the production of volatile fatty acids, such as acetic acid and propionic acid. There are only few anthelmintics targeting nematode energy metabolism. In addition, H. contortus has reduced pathways for amino acid metabolism, polyamine metabolism and nitrogen excretion pathways. Moreover, nucleic acid metabolism comprising purine and pyrimidine salvage pathways as well as lipid metabolism are reduced. In addition, nematodes possess a particular composition of their cuticle. Energy production of adult worms is mainly linked to egg production and complex regulation of the neuromuscular system in both females and males. In this context, microtubules consisting of α- and ß-tubulin heterodimers play a crucial role in the presynaptic vesicle transport. Due to the significant distinction of its quarternary structure in nematodes in comparison to other organisms, ß-tubulin was identified as a major target for benzimidazoles used for anthelmintic treatment. Concerning the function of the neuromuscular system, acetylcholine, a ligand of the nicotinic acetylcholine receptor (nAChR), is the major excitatory neurotransmitter in H. contortus. In contrast, glutamate-gated chloride channels, calcium- and voltage-dependent potassium channels as well as γ-aminobutyric acid (GABA)A and its receptors act as inhibitory neurotransmitters and thus opponents to nAChR. For example, the calcium- and voltage-dependent potassium channel SLO-1 is an important target of emodepside, which is involved in the sensitive regulation of activatory and inhibitory receptors of the nervous system. Most of the modern anthelmintics target these different neuromuscular receptors. The mechanisms of resistance to anthelmintics, either specific or non-specific, are associated with changes in the molecular targets of the drugs, changes in metabolism of the drug (inactivation, removal or prevention of its activation) and/or increased efflux systems. The biochemical and molecular analyses of key developmental, metabolic and structural process of H. contortus still require substantial efforts. The nAChR, glutamate-gated chloride channel and calcium- and voltage-dependent potassium channel SLO-1 have long been known as being essential for nematode survival. Therefore, future research should be intensified to fully resolve the three-dimensional structures of these receptors, as has already been started for glutamate-gated chloride channel. With this knowledge, it should be possible to design new anthelmintics, which possess improved binding capacities to corresponding receptors.
Assuntos
Anti-Helmínticos/farmacologia , Hemoncose/parasitologia , Haemonchus/fisiologia , Nematoides/fisiologia , Infecções por Nematoides/parasitologia , Adaptação Fisiológica , Animais , Descoberta de Drogas , Resistência a Medicamentos , Metabolismo Energético , Haemonchus/efeitos dos fármacos , Haemonchus/genética , Estágios do Ciclo de Vida , Metabolismo dos Lipídeos , Nematoides/efeitos dos fármacosRESUMO
beta-Glucosidase A from bitter almonds was inhibited by the substrate analogue 6-bromo-3,4,5-trihydroxycyclo[2-3H]hex-1-ene oxide. Incorporation of 2 mol inhibitor/mol of dimeric enzyme resulted in total loss of activity. From tryptic digests of the labeled enzyme two radioactive peptides were isolated and their sequence determined (binding site of inhibitor underlined): peptide I, containing approx. 60% of the label: Ile-Thr-Glx-Glx-Gly-Val--Phe-Gly-Asp-Ser-Glx-(Ala, Asx2, Pro)-Lys and peptide II with approx. 30% of the label: Gly-Thr-Glx-Asp. The specifity of the reaction of beta-glucosidases (beta-D-glucoside glucohydrolase, EC 3.2.1.21) with substrate-related epoxides indicates that the aspartic acid labeled in peptide I participates in the catalytic process of beta-glucoside hydrolysis. The labeling of a second site is interpreted in terms of two, mutually exclusive, binding modes of the inhibitor.
Assuntos
Glucosidases , Sementes/enzimologia , beta-Glucosidase , Sequência de Aminoácidos , Aminoácidos/análise , Sítios de Ligação , Nozes , Fragmentos de Peptídeos/análiseRESUMO
The nematode Haemonchus contortus is an important parasite of cattle and sheep. We describe here the cloning of a cDNA encoding a 53 kDa hexokinase (EC 2.7.1.1). The deduced protein shows 73% identity to a 50 kDa hexokinase deduced from a Caenorhabditis elegans cosmid. Alignment with mammalian hexokinases reveals two short amino acid insertions in the H. contortus hexokinase. Software tools for structural protein analysis (ExPASy server, Geneva) localize these insertions on the surface of the molecule, suggesting these surface changes as potential target sites for chemotherapeutic drugs.
Assuntos
Haemonchus/genética , Hexoquinase/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , DNA Complementar/química , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
The Notch signaling pathway has pleiotropic functions during mammalian embryogenesis. It is required for the patterning and differentiation of the presomitic and somitic paraxial mesoderm and of the neural tube. We used DNA-chip expression profiling and 2D-gel electrophoresis combined with peptide mass fingerprinting to identify genes and proteins differentially regulated in E10.5 Dll1 (delta-like 1, Delta1) mutant embryos. The differential expression profiling approach identified 47 regulated transcripts and 40 differentially expressed proteins. The majority of these genes has until now not been associated with Notch signaling. Subsequent whole-mount in situ hybridization confirmed that a subset of the identified transcripts has restricted and distinct patterns of expression in E10.5 mouse embryos. For most genes these expression patterns were affected in the presomitic mesoderm, in differentiating somites of Dll1 mutant embryos and in the neural tube and cells differentiating from it. Similar effects were observed in embryos homozygous for the Headturner (Htu) and pudgy (pu) mutations, which are alleles of the Notch ligands Jag1 and Dll3. The regulated expression of a subset of the proteins was validated by immunoblots. Remarkably six of the proteins down-regulated in Dll1 mutant embryos are proteasome subunits. The large set of regulated genes identified in this differential expression profiling approach is an important resource for further functional studies.
Assuntos
Padronização Corporal/genética , Desenvolvimento Embrionário/genética , Perfilação da Expressão Gênica , Proteínas de Membrana/fisiologia , Animais , Proteínas de Ligação ao Cálcio/genética , Embrião de Mamíferos/química , Embrião de Mamíferos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Peptídeos e Proteínas de Sinalização Intercelular , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteína Jagged-1 , Proteínas de Membrana/genética , Camundongos , Camundongos Mutantes , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas/análise , Proteínas/genética , Proteínas/metabolismo , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Proteínas Serrate-Jagged , Transdução de SinaisRESUMO
Besides 24-membered cyclooctadepsipeptides (CODPs) with the most prominent member of this class emodepside, the structurally related 18-membered cyclohexadepsipeptides (CHDPs) were of interest with regard to their efficacy against the nematode H. contortus in sheep.The CHDPs prepared by a simple total synthesis represent enniatin derivatives with strong in vivo activity against H. contortus in sheep. The correlation between the nature of the CHDP major conformers and their anthelmintic activities was studied in detail. All CHDPs with strong in vivo activity exists in deuterochloroform solution as conformers with restricted flexibility which was found by 2D-NMR spectroscopic analysis. This reduced flexibility of the major conformer can be exemplified by CHDPs containing e.g.: (i) an unsymmetrically folded conformation with no cis-amide bound, (ii) an internal hydrogen bond or (iii) one cis-amide bond, respectively.The strong in vivo anthelmintic activity against H. contortus in sheep indicates that the stereochemistry in 2-position of CHDPs is less important for their high inding affinity. It may be assumed that the identified inflexible region of the major conformers might mimic the active conformation of these CHDPs, which could be helpful for rational design of anthelmintics with less complicated structures.
Assuntos
Anti-Helmínticos/farmacologia , Depsipeptídeos/farmacologia , Hemoncose/veterinária , Haemonchus/efeitos dos fármacos , Doenças dos Ovinos/tratamento farmacológico , Animais , Depsipeptídeos/química , Hemoncose/tratamento farmacológico , Modelos Moleculares , Estrutura Molecular , Ovinos , Doenças dos Ovinos/parasitologia , Relação Estrutura-AtividadeRESUMO
The research of the class of cyclic octadepsipeptides started at the beginning of the 1990s. PF1022A, the starting material of emodepside, is a natural secondary metabolite of the fungus Mycelia sterilia, which belongs to the microflora of the leaves of Camellia japonica. PF1022A consists of four N-methyl-L-leucins, two D-Iactic acids and two D-phenyllactic acids, which build up a cyclic octadepsipeptide with an alternating L-D-L-configuration. Emodepside is a semisynthetic derivative of PF1022A, which contains a morpholine attached in para position at each of both D-phenyllactic acids. Emodepside is efficacious against a variety of gastrointestinal nematodes. Emodepside binds to a presynaptic latrophilin receptor in nematodes. The following presynaptic signal transduction occurs via activation of Gqalpha protein and phospholipase-Cbeta, which leads to mobilization of diacylglycerol (DAG). DAG then activates UNC-13 and synaptobrevin, two proteins which play an important role in presynaptic vesicle-functioning. This finally leads to the release of a currently unidentified transmitter. The transmitter (or modulator) exerts its effects at the postsynaptic membrane and induces a flaccid paralysis of the pharynx and the somatic musculature in nematodes.
Assuntos
Anti-Helmínticos/química , Anti-Helmínticos/farmacologia , Depsipeptídeos/química , Depsipeptídeos/farmacologia , Animais , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Resistência a Medicamentos , Estrutura Molecular , Nematoides/efeitos dos fármacos , Nematoides/genética , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/veterinária , Filogenia , Folhas de Planta , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/parasitologiaRESUMO
The 24-membered cyclooctadepsipeptide (CODP) PF1022A, the active metabolite of the fungus imperfectus Mycelia sterilia (Rosellinia sp.) isolated from the plant Camellia japonica in Japan, is described as a powerful broad-spectrum anthelmintic natural product with low toxicity in animals. Further CODPs such as PF1022B, C, D and E have been isolated from the same culture and their structures have been established. Both PF1022A and PF1022E serve as valuable starting materials for the synthesis of semi-synthetic CODP derivatives with improved intrinsic anthelmintic potency and broad-spectrum activity. It was found that in most cases the di-substituted PF1022A derivatives showed a greater (or equal) activity by oral application against the gastrointestinal nematode Haemonchus contortus compared to the corresponding mono-substituted PF1022A analogues as exemplified by emodepside. In order to get additional information on the bioactive conformation, emodepside was transformed into its mono- and tetra-thionated derivatives by isosteric replacement. In the light of the increased efficacy of these derivatives against H. contortus or Trichostrongylus colubriformis, it has been suggested that the asymmetric conformation clearly influences the anthelmintic activity of CODPs. Although useful synthetic pathways are available today for the preparation of the semi-synthetic CODP emodepside, the fermentative production of its bis-para-nitro and bis-para-amino precursors could be the process used for its industrial-scale production in the future.
Assuntos
Anti-Helmínticos/química , Depsipeptídeos/química , Depsipeptídeos/síntese química , Peptídeos Cíclicos/química , Animais , Relação Dose-Resposta a Droga , Desenho de Fármacos , Haemonchus/efeitos dos fármacos , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Parasitic nematodes cause major problems in livestock animals. Resistances to the most commonly used drugs are arising. The cyclooctadepsipeptide emodepside belongs to a new class of anthelmintics. A receptor for emodepside, Hc110-R, was previously identified in Haemonchus contortus. We have identified the complete coding sequences of putative orthologues in Cooperia oncophora and Ostertagia ostertagi, tri-chostrongyles in cattle. The putative receptors were named depsiphilins. The deduced amino acid sequence of C. oncophora depsiphilin has a similarity of 91% to the O. ostertagi sequence. The similarity of both the C. oncophora and O. ostertagi depsiphilin to Hc110-R is 89%, based on the amino acid sequence. The depsiphilins share 46% identity with the latrophilin-like protein 1 in Caenorhabditis elegans and 47% identity with a hypothetical protein in Caenorhabditis briggsae. Hc110-R and the latrophilin-like proteins of C. elegans were previously reported to be putative G protein-coupled receptors (GPCRs) and to be related to mammalian latrophilins. A seven transmembrane domain, a GPCR proteolytic site, and other conserved domains characteristic of receptors of the latrophilin group were identified within the depsiphilins. Therefore it seems reasonable to allocate the depsiphilins to the previously described latrophilins and latrophilin-like proteins.
Assuntos
Anti-Helmínticos/farmacologia , Depsipeptídeos/farmacologia , Receptores Acoplados a Proteínas G/metabolismo , Trichostrongyloidea/metabolismo , Sequência de Aminoácidos , Animais , Anti-Helmínticos/química , Depsipeptídeos/química , Regulação da Expressão Gênica , Dados de Sequência Molecular , Filogenia , Receptores Acoplados a Proteínas G/genética , Trichostrongyloidea/efeitos dos fármacosRESUMO
A new combination of two anthelmintic compounds containing emodepside and praziquantel (Profender, Bayer AG, Levekusen, Germany) was tested in pet rodents and reptiles. Topical application of the two compounds led to the quick disappearance of nematodes and cestodes from a broad spectrum of hosts including mice, jirds, snakes, anole lizards, turtles, monitor lizards, etc. In reptiles the dosage had to be increased, since the thick outer layer of the epidermis hinders the penetration of the compounds. In animals with an extremely thick epidermis (e.g. monitor lizards, leguans) the new product was applied under the armpits.
Assuntos
Infecções por Cestoides/veterinária , Depsipeptídeos/uso terapêutico , Infecções por Nematoides/veterinária , Praziquantel/uso terapêutico , Répteis/parasitologia , Administração Tópica , Animais , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/uso terapêutico , Infecções por Cestoides/tratamento farmacológico , Depsipeptídeos/administração & dosagem , Quimioterapia Combinada , Gerbillinae/parasitologia , Camundongos , Infecções por Nematoides/tratamento farmacológico , Praziquantel/administração & dosagemRESUMO
Peripheral nerve sheath tumours are hallmarks of neurofibromatosis type 1 (NF1). Development of plexiform neurofibromas to malignant peripheral nerve sheath tumours (MPNST) is common. The NF1 gene promoter harbours a hypomethylated CpG island. Thus, methylation changes may be involved in the development of different types of neurofibromas and malignant transformation. We investigated NF1-associated dermal (n=9) and plexiform neurofibromas (n=7), MPNST (n=5) and non-NF1 leucocyte samples (n=20) for their methylation pattern by bisulphite genomic sequencing. We could not find global hypermethylation in the NF1 promoter in our series. Nevertheless, site-specific methylation, involving transcription factor binding sites for SP1, CRE (-10), and AP-2, was observed. One region of the 5'-UTR (untranslated region) overlapping with a putative AP-2 binding site was methylated at 30-100% in 4/20 control samples. In conclusion, we did not find hypermethylation in NF1-associated tumours. Instead, low level methylation could parallel a global genomic hypomethylation in malignancy.
Assuntos
Neoplasias de Bainha Neural/metabolismo , Neurofibromatose 1/metabolismo , Regiões Promotoras Genéticas/genética , Antioxidantes/metabolismo , Células Clonais , Metilação de DNA , DNA de Neoplasias/metabolismo , Feminino , Humanos , Leucócitos/metabolismo , Perda de Heterozigosidade , Masculino , Dados de Sequência Molecular , Neoplasias de Bainha Neural/genética , Neurofibromatose 1/genética , Reação em Cadeia da Polimerase/métodos , Sulfitos/metabolismo , Transcrição GênicaRESUMO
Praziquantel induces a bilayer to isotropic transition in the absence of Ca2+ in a mixed phospholipid membrane consisting of phosphatidylethanolamine (PE) and phosphatidylserine (PS) at a molar ratio of 2:1 at 25 degrees C or 35 degrees C, irrespective of the lipid/drug molar ratio (10:1; 2:1). Addition of Ca2+ at different PS/Ca2+ molar ratios (4:1, 2:1 or 1:1) leads to a transition to a hexagonal (HII) state. With a phospholipid membrane of different composition (PE/PS molar ratio 4:1) praziquantel exerts quite different effects in the presence of Ca2+ (PS/Ca2+ molar ratio 1:1). An isotropic-signal appears together with a bilayer one at 25 degrees C, while a HII-signal can be detected at 35 degrees C. Thus, two separate phases coexist at this PE/PS molar ratio, while at a PE/PS molar ratio of 2:1, praziquantel and Ca2+ induce only a HII-signal. The results with these model membranes show that praziquantel and Ca2+ exert drastic influences on bilayer-isotropic-hexagonal transitions. The possibility that this drug might act in the schistosomal tegumental membranes in the same way is discussed.
Assuntos
Cálcio/farmacologia , Bicamadas Lipídicas/metabolismo , Praziquantel/farmacologia , Animais , Espectroscopia de Ressonância Magnética , Modelos Biológicos , Fosfatidiletanolaminas/metabolismo , Fosfatidilserinas/metabolismoRESUMO
Real-time PCR assays were developed to identify and quantify common gastrointestinal nematodes of ruminants. The assays were based on genus-specific primer and probe combinations derived from the second internal transcribed spacer (ITS2) ribosomal DNA transcription unit of Haemonchus contortus, Ostertagia leptospicularis, Trichostrongylus colubriformis and Cooperia curticei. The TaqMan probes for the first two species were labelled with 6-carboxyfluorescein and those for the latter two with VIC and all were synthesised as dihydrocyclopyrroloindole minor groove binder conjugates. Cloned ITS2 DNA or genomic DNA isolated from first stage larvae, derived from overnight cultures, were used as template. The real-time PCRs reproducibly allowed the identification of at least 100 copies of cloned ITS2 DNA or one hundredth part of a single larval genomic DNA equivalent. The assays proved to be genus-specific since the addition of DNA from heterologous trichostrongyle genera did not change the cycle threshold values obtained with only homologous DNA. Furthermore, the use of genomic DNA of several other ruminant nematode parasite genera gave negative results. In duplex experiments, 6-carboxyfluorescein-labelled H. contortus or O. leptospicularis probes were used together with the VIC-labelled T. colubriformis and C. curticei probes, respectively, confirming the specificity and sensitivity of the probes found in the simplex experiments. The primer and probe combinations gave comparable results when applied with core reagents from different suppliers and with both the M x 4000 and the ABI 7700 instruments. This technique provides means for a rapid, reliable and quantitative detection and differentiation of the most important parasitic nematodes of sheep and cattle.