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1.
Med Ultrason ; 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38150699

RESUMO

The diagnosis or rare mesenchymal malignant lesions of the liver may be a challenge owing to the rarity of the disease and is usually made by histological confirmation. An ultrasound examination with, if required, color Doppler sonography and contrast-enhanced ultrasound, taking into account the clinical background of the patient, may help to focus the differential diagnosis. In this review, we describe the pathological and ultrasound features of several rare mesenchymal malignant liver lesions which include undifferentiated sarcoma of the liver, leiomyosarcoma, angiosarcoma, fibrosarcoma, liposarcoma, and epithelioid hemangioendothelioma.

2.
Clin Nutr ; 42(6): 899-908, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37086618

RESUMO

BACKGROUND & AIM: For older adults, the dietary protein intake has shown to be skewed towards the evening meal. Resultingly, the vital source of essential amino acids could be insufficient after some meals, while after the evening meal the dietary protein could be suboptimally utilized for protein synthesis. The present study explored if an even distribution of the protein intake could improve the dietary amino acid absorption and whole-body protein net-balance. METHODS: Twenty-four healthy elderly males and females were included in a randomized controlled trial. Ten days of habituation to either an EVEN (n = 12) or SKEWED (n = 12) protein intake, was followed by a trial day. The total protein intake was controlled at 1.5 g/kg LBM, divided into 30% at each main meal in EVEN, and into 15% at breakfast and lunch and 60% at dinner in SKEWED. Snacks with 5% of the protein intake were served between meals. Energy intake in the meals and snacks were equal in both groups. Intrinsically labelled 2H5-phenylalanine minced meat was served as the dietary protein to assess the amino acid absorption. On the trial day, infusion of 2H8-phenylalanine and 2H2-tyrosine, and blood samples taken over 11 h were used to measure whole-body protein turnover. Vastus lateralis muscle biopsies were taken to measure 9 h muscle protein FSR. RESULTS: Amino acid absorption rates and concentrations were greater in EVEN compared to SKEWED protein intake. Whole-body protein breakdown rates were lower with similar protein synthesis rates, and consequently the net-balance was greater in EVEN after breakfast and lunch compared to SKEWED and were the same in both groups after dinner. Muscle protein FSR were not different between EVEN and SKEWED. CONCLUSIONS: The whole-body protein net-balance was more positive in EVEN compared to SKEWED for an extended time of the measured period, driven by a lower whole-body protein breakdown in EVEN. CLINICAL TRIALS REGISTRATION: NCT03870425, https://clinicaltrials.gov/ct2/show/NCT03870425.


Assuntos
Dieta , Proteínas Alimentares , Masculino , Feminino , Humanos , Idoso , Proteínas Alimentares/metabolismo , Proteínas Musculares/metabolismo , Fenilalanina , Aminoácidos , Refeições
3.
Med Ultrason ; 25(1): 56-65, 2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-34762719

RESUMO

The vast majority of clinicians associate diagnostic ultrasound with a tool that is designed for the living patient. However, it is of course possible to apply this imaging technology to evaluate the recently deceased patient for postmortem diagnosis, or even just examine postmortem tissue. We describe several cases in which ultrasound-enabled providers obtain answers in postmortem examinations and discuss potential future strategies and applications. In addition, we will also illustrate the use of sonography in minimally invasive post-mortem tissue sampling (MITS), an approach that can be used in post-mortem minimally invasive autopsies as well as for establishing ultrasound diagnostic parameters in new medical fields such as periodontal and dental implant specialties.


Assuntos
Ultrassonografia , Humanos , Ultrassonografia/métodos , Autopsia/métodos
4.
Nutrients ; 14(21)2022 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-36364705

RESUMO

Sarcopenia is a multifactorial disease that limits autonomy for the growing elderly population. An optimal amount of dietary protein has shown to be important to maintain muscle mass during aging. Yet, the optimal distribution of that dietary protein has not been fully clarified. The aim of the present study was to examine whether an even, compared to a skewed, distribution of daily dietary protein leads to higher muscle protein synthesis and amino acid utilization. Twelve healthy males and twelve healthy females aged between 65 and 80 years were block randomized to either an even (EVEN, n = 12) or skewed (SKEWED, n = 12) dietary protein distribution for three daily main meals. Seven days of habituation were followed by three trial days, which were initiated by oral intake of deuterium oxide (D2O). The dietary protein throughout all trial meals was intrinsically labelled with 2H5-phenylalanine. Blood samples were drawn daily, and muscle biopsies were taken before and at the end of the trial to measure muscle protein synthesis (FSR) and muscle protein incorporation of the dietary-protein-derived tracer. Muscle protein FSR was no different between the two groups (EVEN 2.16 ± 0.13%/day and SKEWED 2.23 ± 0.09%/day, p = 0.647), and the muscle protein incorporation of the intrinsically labeled 2H5-phenylalanine tracer was not different between the two groups (EVEN 0.0049 ± 0.0004 MPE% and SKEWED 0.0054 ± 0.0003 MPE%, p = 0.306). In conclusion, the daily distribution pattern of the dietary protein did not affect muscle protein synthesis or the utilization of dietary protein.


Assuntos
Aminoácidos , Proteínas Musculares , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Proteínas Alimentares/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Fenilalanina
5.
Antibiotics (Basel) ; 11(8)2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-36009951

RESUMO

BP214 is an all-D antimicrobial peptide amide, kklfkkilryl, which shows an excellent activity against colistin-resistant Acinetobacter baumannii and a low hemolytic activity. The aim of the present work was to investigate how C-terminus-to-side chain macrocyclization and fatty acid modification affect the antimicrobial and hemolytic activity of this peptide. In total, 18 analogs of BP214 were synthesized using a combination of Fmoc-based solid-phase peptide synthesis and the submonomer approach. Cyclization was achieved by reacting the ε-amino group of a C-terminal lysine residue with a bromoacetylgroup attached to the Nα amino group of the N-terminal amino acid, generating a secondary amine at which the exocyclic lipopeptide tail was assembled. Three different ring sizes (i.e., 3-5 amino acid residues) of C-locked analogs combined with fatty acids of different lengths (i.e., C10-C14) were investigated. The antimicrobial activity of the analogs was tested against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. The most promising compound was analog 13 (MIC = 4 µg/mL (2.4 µM) against E. coli and 36% hemolysis of red blood cells at 150 µM). In a time-kill assay, this peptide showed a significant, concentration-dependent reduction in viable E. coli cells comparable to that seen for colistin.

6.
Eur J Nutr ; 61(5): 2475-2491, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35182194

RESUMO

PURPOSE: This study investigates if co-ingestion of cluster dextrin (CDX) augments the appearance of intrinsically labeled meat protein hydrolysate-derived amino acid (D5-phenylalanine), Akt/mTORC1 signaling, and myofibrillar protein fractional synthetic rate (FSR). METHODS: Ten moderately trained healthy males (age: 21.5 ± 2.1 years, body mass: 75.7 ± 7.6 kg, body mass index (BMI): 22.9 ± 2.1 kg/m2) were included for a double-blinded randomized controlled crossover trial. Either 75 g of CDX or glucose (GLC) was given in conjunction with meat protein hydrolysate (0.6 g protein * FFM-1) following a whole-body resistance exercise. A primed-continuous intravenous infusion of L-[15N]-phenylalanine with serial muscle biopsies and venous blood sampling was performed. RESULTS: A time × group interaction effect was found for serum D5-phenylalanine enrichment (P < 0.01). Serum EAA and BCAA concentrations showed a main effect for group (P < 0.05). Tmax serum BCAA was greater in CDX as compared to GLC (P < 0.05). However, iAUC of all serum parameters did not differ between CDX and GLC (P > 0.05). Tmax serum EAA showed a trend towards a statistical significance favoring CDX over GLC. The phosphorylation of p70S6KThr389, rpS6Ser240/244, ERK1/2Thr202/Tyr204 was greater in CDX compared to GLC (P < 0.05). However, postprandial myofibrillar FSR did not differ between CDX and GLC (P = 0.17). CONCLUSION: In moderately trained younger males, co-ingestion of CDX with meat protein hydrolysate does not augment the postprandial amino acid availability or myofibrillar FSR as compared to co-ingestion of GLC during the recovery from a whole-body resistance exercise despite an increased intramuscular signaling. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03303729 (registered on October 3, 2017).


Assuntos
Dextrinas , Treinamento Resistido , Adulto , Aminoácidos , Estudos Cross-Over , Ingestão de Alimentos , Humanos , Masculino , Proteínas Musculares , Músculo Esquelético/metabolismo , Fenilalanina , Hidrolisados de Proteína/metabolismo , Adulto Jovem
7.
Z Gastroenterol ; 59(12): 1309-1321, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34768289

RESUMO

Infektiöse fokale Leberläsionen (FLL) treten in der klinischen Praxis häufig auf, wobei bakterielle Leberabszesse die Hälfte ausmachen. Eine genaue Diagnose der FLL ist für die Auswahl der am besten geeigneten Therapie und zur Vorbeugung von Komplikationen unerlässlich. Ziel der aktuellen Arbeit ist es, den Nutzen von Ultraschall und kontrastmittelverstärktem Ultraschall (CEUS) zur Erkennung und Charakterisierung infektiöser Leberläsionen zu beschreiben.


Assuntos
Neoplasias Hepáticas , Humanos
8.
PLoS One ; 16(9): e0257167, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34529717

RESUMO

A potentiostat is an essential piece of analytical equipment for studying electrochemical devices and reactions. As the design of electrochemical devices evolve, applications for systems with multiple working electrodes have become more common. These applications drive a need for low-cost multi-channel potentiostat systems. We have developed a portable, low-cost and scalable system with a modular design that can support 8 to 64 channels at a cost as low as $8 per channel. This design can replace the functionality of commercial potentiostats which cost upwards of $10k for certain applications. Each channel in the multi-channel potentiostat has an independent adjustable voltage source with a built-in ammeter and switch, making the device flexible for various configurations. The multi-channel potentiostat is designed for low current applications (nA range), but its purpose can change by varying its shunt resistor value. The system can either function as a standalone device or remotely controlled. We demonstrate the functionality of this system for the control of a 24-channel bioelectronic ion pump for open- and closed- loop control of pH.


Assuntos
Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Paládio/química
9.
J Antimicrob Chemother ; 76(11): 2802-2814, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34450639

RESUMO

BACKGROUND: Antisense peptide nucleic acids (PNAs) constitute an alternative to traditional antibiotics, by their ability to silence essential genes. OBJECTIVES: To evaluate the antibacterial effects of antisense PNA-peptide conjugates that target the gene encoding the alpha subunit (NrdA) of the Escherichia coli ribonucleotide reductase (RNR). METHODS: Bacterial susceptibility of a series of NrdA-targeting PNAs was studied by MIC determination and time-kill analysis. Western-blot analysis, gene complementation and synergy with hydroxyurea were employed to determine the efficiency of NrdA-PNA antisense treatment. The effect on chromosome replication was addressed by determining the DNA synthesis rate, by flow cytometry analysis, by quantitative PCR and by fluorescence microscopy. The use of DNA repair mutants provided insight into the bactericidal action of NrdA-PNA. RESULTS: Treatment with NrdA-PNA specifically inhibited growth of E. coli, as well as NrdA protein translation at 4 µM. Also, the DNA synthesis rate was reduced, preventing completion of chromosome replication and resulting in formation of double-stranded DNA breaks and cell death. CONCLUSIONS: These data present subunits of the NrdAB RNR as a target for future antisense microbial agents and provide insight into the bacterial physiological response to RNR-targeting antimicrobials.


Assuntos
Ácidos Nucleicos Peptídicos , Ribonucleotídeo Redutases , Antibacterianos/farmacologia , DNA , Escherichia coli/genética , Ácidos Nucleicos Peptídicos/farmacologia , Ribonucleotídeo Redutases/genética
10.
Biomolecules ; 11(2)2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670478

RESUMO

Escherichia coli is responsible for cases of diarrhea around the world, and some studies have shown the benefits of cinnamaldehyde in the treatment of bacterial disease. Therefore, the objective of this study was to evaluate the effects of cinnamaldehyde in mice colonized by pathogenic E. coli, as well as to provide more insights into its antimicrobial action mechanism. After determination of minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations, the interference of cinnamaldehyde in macromolecular pathways (synthesis of DNA, RNA, protein, and cell wall) was measured by incorporation of radioisotopes. The anti-adhesive properties of cinnamaldehyde towards E. coli 042 were evaluated using human epithelial type 2 (HEp-2) cells. Intestinal colonization was tested on mice, and the effect of cinnamaldehyde on Tenebrio molitor larvae. Cinnamaldehyde showed MIC and MBC values of 780 µg/mL and 1560 µg/mL, respectively; reduced the adhesion of E. coli 042 on HEp-2 cells; and affected all the synthetic pathways evaluated, suggesting that compost impairs the membrane/cell wall structure leading bacteria to total collapse. No effect on the expression of genes related to the SOS pathway (sulA and dinB1) was observed. The compound did not interfere with cell viability and was not toxic against T. molitor larvae. In addition, cinnamaldehyde-treated mice exhibited lower levels of colonization by E. coli 042 than the untreated group. Therefore, the results show that cinnamaldehyde is effective in treating the pathogenic E. coli strain 042 and confirm it as a promising lead molecule for the development of antimicrobial agents.


Assuntos
Acroleína/análogos & derivados , Escherichia coli/efeitos dos fármacos , Acroleína/farmacologia , Animais , Antibacterianos/farmacologia , Produtos Biológicos/farmacologia , Humanos , Intestinos/microbiologia , Camundongos , Testes de Sensibilidade Microbiana , Tenebrio/microbiologia
11.
Int J Cardiovasc Imaging ; 37(5): 1781-1788, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33502653

RESUMO

AIMS: The aim of the study was to identify the characteristics of the culprit lesions compared to non-culprit lesions in patients with non-ST-elevation-myocardial infarction using dual energy computed tomography (DECT). METHODS AND RESULTS: In 29 patients, we identified 29 culprit lesions and 227 non-culprit lesions. Quantitative values such as the effective atomic number (effective-Z) and Hounsfield Units (HU) values were measured. Furthermore, all the lesions were characterised using characteristics such as composition (non-calcified, predominantly-non-calcified, predominantly-calcified, or calcified), presence of spotty calcification, remodelling index, and napkin ring sign. The mean effective-Z and HU values were significantly lower in culprit lesions than in non-culprit lesions (8.99 ± 1.21 vs 9.79 ± 1.52; p = 0.0066 and 87.41 ± 84.97 vs. 154.45 ± 176.13; p = 0.0447). The culprit lesions had a higher frequency of non-calcified plaques and predominantly non-calcified plaques, and were with a greater presence of napkin ring signs in comparison with non-culprit lesions. There were no differences in the presence of spotty calcification or remodelling index. By adding effective-Z to plaque characteristics such as non-calcified, positive remodelling, spotty calcification, and napkin rings we observed a significant increased sensitivity of detecting culprit lesions (65.5% vs.44.8%), but no significant changes in area under curve (AUC). CONCLUSION: The use of DECT adds new information of the plaque composition expressed by the effective-Z, which differs significantly in culprit lesions in comparison with non-culprit lesions. The use of the effective-Z improves the diagnostic sensitivity in detection of culprit lesions.


Assuntos
Doença da Artéria Coronariana , Infarto do Miocárdio sem Supradesnível do Segmento ST , Placa Aterosclerótica , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Humanos , Valor Preditivo dos Testes , Tomografia Computadorizada por Raios X
12.
Ultraschall Med ; 42(2): 178-186, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32663881

RESUMO

BACKGROUND: This prospective multicenter study funded by the DEGUM assesses the diagnostic accuracy of standardized contrast-enhanced ultrasound (CEUS) for the noninvasive diagnosis of hepatocellular carcinoma (HCC) in high-risk patients. METHODS: Patients at high risk for HCC with a histologically proven focal liver lesion on B-mode ultrasound were recruited prospectively in a multicenter approach. Clinical and imaging data were entered via online entry forms. The diagnostic accuracies for the noninvasive diagnosis of HCC were compared for the conventional interpretation of standardized CEUS at the time of the examination (= CEUS on-site) and the two CEUS algorithms ESCULAP (Erlanger Synopsis for Contrast-enhanced Ultrasound for Liver lesion Assessment in Patients at risk) and CEUS LI-RADS (Contrast-Enhanced UltraSound Liver Imaging Reporting and Data System). RESULTS: 321 patients were recruited in 43 centers; 299 (93.1 %) had liver cirrhosis. The diagnosis according to histology was HCC in 256 cases, and intrahepatic cholangiocarcinoma (iCCA) in 23 cases. In the subgroup of cirrhotic patients (n = 299), the highest sensitivity for the diagnosis of HCC was achieved with the CEUS algorithm ESCULAP (94.2 %) and CEUS on-site (90.9 %). The lowest sensitivity was reached with the CEUS LI-RADS algorithm (64 %; p < 0.001). However, the specificity of CEUS LI-RADS (78.9 %) was superior to that of ESCULAP (50.9 %) and CEUS on-site (64.9 %; p < 0.001). At the same time, the negative predictive value (NPV) of CEUS LI-RADS was significantly inferior to that of ESCULAP (34.1 % vs. 67.4 %; p < 0.001) and CEUS on-site (62.7 %; p < 0.001). The positive predictive values of all modalities were high (around 90 %), with the best results seen for CEUS LI-RADS and CEUS on-site. CONCLUSION: This is the first multicenter, prospective comparison of standardized CEUS and the recently developed CEUS-based algorithms in histologically proven liver lesions in cirrhotic patients. Our results reaffirm the excellent diagnostic accuracy of CEUS for the noninvasive diagnosis of HCC in high-risk patients. However, on-site diagnosis by an experienced examiner achieves an almost equal diagnostic accuracy compared to CEUS-based diagnostic algorithms.


Assuntos
Neoplasias dos Ductos Biliares , Carcinoma Hepatocelular , Neoplasias Hepáticas , Algoritmos , Carcinoma Hepatocelular/diagnóstico por imagem , Meios de Contraste , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Imageamento por Ressonância Magnética , Estudos Prospectivos , Ultrassonografia
14.
Int J Mol Sci ; 21(16)2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823798

RESUMO

Multidrug-resistant bacteria are a global health problem. One of the last-resort antibiotics against Gram-negative bacteria is the cyclic lipopeptide colistin, displaying a flexible linker with a fatty acid moiety. The aim of the present project was to investigate the effect on antimicrobial activity of introducing fatty acid moieties of different lengths and in different positions in a cyclic peptide, S3(B), containing a flexible linker. The lipidated analogues of S3(B) were synthesized by 9-fluorenylmethoxycarbonyl (Fmoc) solid-phase peptide synthesis. Following assembly of the linear peptide by Fmoc solid-phase peptide synthesis, on-resin head-to-tail cyclization and fatty acid acylation were performed. The antimicrobial activity was determined against the ESKAPE pathogens, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, hemolytic activity was determined against human erythrocytes. A total of 18 cyclic lipopeptides were synthesized and characterized. It was found that introduction of fatty acids in positions next to the flexible linker was more strongly linked to antimicrobial activity. The fatty acid length altered the overall hydrophobicity, which was the driving force for both high antimicrobial and hemolytic activity. Peptides became highly hemolytic when carbon-chain length exceeded 10 (i.e., C10), overlapping with the optimum for antimicrobial activity (i.e., C8-C12). The most promising candidate (C8)5 showed antimicrobial activity corresponding to that of S3(B), but with an improved hemolytic profile. Finally, (C8)5 was further investigated in a time-kill experiment.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Lipopeptídeos/química , Lipopeptídeos/farmacologia , Acilação , Antibacterianos/síntese química , Ciclização , Ácidos Graxos/química , Hemólise/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Lipopeptídeos/síntese química , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos
15.
Antibiotics (Basel) ; 9(7)2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32629881

RESUMO

The emergence of multi-drug resistant bacteria is becoming a major health concern. New strategies to combat especially Gram-negative pathogens are urgently needed. Antimicrobial peptides (AMPs) found in all multicellular organisms act as a first line of defense in immunity. In recent years, AMPs have attracted increasing attention as potential antibiotics. Naturally occurring antimicrobial cyclic lipopeptides include colistin and daptomycin, both of which contain a flexible linker. We previously reported a cyclic AMP BSI-9 cyclo(Lys-Nal-Lys-Lys-Bip-O2Oc-Nal-Lys-Asn) containing a flexible linker, with a broad spectrum of activity against bacterial strains and low hemolytic activity. In this study, improvement of the antimicrobial activity of BSI-9, against the European Committee on Antimicrobial Susceptibility Testing (EUCAST) strains of S. aureus, E. coli, A. baumannii, and P. aeruginosa was examined. This led to synthesis of eighteen peptide analogues of BSI-9, produced in four individual stages, with a different focus in each stage; cyclization point, hydrophobicity, cationic side-chain length, and combinations of the last two. Specifically the modified compound 11, exhibited improved activity against Staphylococcus aureus and Pseudomonas aeruginosa with MIC of 4 µg/mL and 8 µg/mL, respectively, compared to the original BSI-9, which had an MIC of 16-32 µg/mL.

16.
Molecules ; 24(24)2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31847173

RESUMO

The increasing emergence of multi-drug resistant bacteria is a serious threat to public health worldwide. Antimicrobial peptides have attracted attention as potential antibiotics since they are present in all multicellular organisms and act as a first line of defence against invading pathogens. We have previously identified a small all-d antimicrobial octapeptide amide kk(1-nal)fk(1-nal)k(nle)-NH2 (D2D) with promising antimicrobial activity. In this work, we have performed a structure-activity relationship study of D2D based on 36 analogues aimed at discovering which elements are important for antimicrobial activity and toxicity. These modifications include an alanine scan, probing variation of hydrophobicity at lys5 and lys7, manipulation of amphipathicity, N-and C-termini deletions and lys-arg substitutions. We found that the hydrophobic residues in position 3 (1-nal), 4 (phe), 6 (1-nal) and 8 (nle) are important for antimicrobial activity and to a lesser extent cationic lysine residues in position 1, 2, 5 and 7. Our best analogue 5, showed MICs of 4 µg/mL against A. baumannii, E. coli, P. aeruginosa and S. aureus with a hemolytic activity of 47% against red blood cells. Furthermore, compound 5 kills bacteria in a concentration-dependent manner as shown by time-kill kinetics. Circular dichroism (CD) spectra of D2D and compounds 1-8 showed that they likely fold into α-helical secondary structure. Small angle x-ray scattering (SAXS) experiments showed that a random unstructured polymer-like chains model could explain D2D and compounds 1, 3, 4, 6 and 8. Solution structure of compound 5 can be described with a nanotube structure model, compound 7 can be described with a filament-like structure model, while compound 2 can be described with both models. Lipid interaction probed by small angle X-ray scattering (SAXS) showed that a higher amount of compound 5 (~50-60%) inserts into the bilayer compared to D2D (~30-50%). D2D still remains the lead compound, however compound 5 is an interesting antimicrobial peptide for further investigations due to its nanotube structure and minor improvement to antimicrobial activity compared to D2D.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Acinetobacter baumannii/efeitos dos fármacos , Dicroísmo Circular , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-Atividade , Difração de Raios X
17.
J Antimicrob Chemother ; 73(2): 414-424, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29092042

RESUMO

Objectives: To characterize NAI-107 and related lantibiotics for their in vitro activity against Gram-negative pathogens, alone or in combination with polymyxin, and against non-dividing cells or biofilms of Staphylococcus aureus. NAI-107 was also evaluated for its propensity to select or induce self-resistance in Gram-positive bacteria. Methods: We used MIC determinations and chequerboard experiments to establish the antibacterial activity of the examined compounds against target microorganisms. Time-kill assays were used to evaluate killing of exponential and stationary-phase cells. The effects on biofilms (growth inhibition and biofilm eradication) were evaluated using biofilm-coated pegs. The frequency of spontaneous resistant mutants was evaluated by either direct plating or by continuous sub-culturing at 0.5 × MIC levels, followed by population analysis profiles. Results: The results showed that NAI-107 and its brominated variant are highly active against Neisseria gonorrhoeae and some other fastidious Gram-negative pathogens. Furthermore, all compounds strongly synergized with polymyxin against Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and showed bactericidal activity. Surprisingly, NAI-107 alone was bactericidal against non-dividing A. baumannii cells. Against S. aureus, NAI-107 and related lantibiotics showed strong bactericidal activity against dividing and non-dividing cells. Activity was also observed against S. aureus biofilms. As expected for a lipid II binder, no significant resistance to NAI-107 was observed by direct plating or serial passages. Conclusions: Overall, the results of the current work, along with previously published results on the efficacy of NAI-107 in experimental models of infection, indicate that this lantibiotic represents a promising option in addressing the serious threat of antibiotic resistance.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Biofilmes/efeitos dos fármacos , Sinergismo Farmacológico , Bactérias Gram-Negativas/efeitos dos fármacos , Polimixinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Bactérias Gram-Negativas/fisiologia , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos
18.
ACS Med Chem Lett ; 7(8): 741-5, 2016 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-27563396

RESUMO

Bacterial resistance to antibiotic therapy is on the rise and threatens to evolve into a worldwide emergency: alternative solutions to current therapies are urgently needed. Cationic amphipathic peptides are potent membrane-active agents that hold promise as the next-generation therapy for multidrug-resistant infections. The peptides' behavior upon encountering the bacterial cell wall is crucial, and much effort has been dedicated to the investigation and optimization of this amphipathicity-driven interaction. In this study we examined the interaction of a novel series of nine-membered flexible cyclic AMPs with liposomes mimicking the characteristics of bacterial membranes. Employed techniques included circular dichroism and marker release assays, as well as microbiological experiments. Our analysis was aimed at correlating ring flexibility with their antimicrobial, hemolytic, and membrane activity. By doing so, we obtained useful insights to guide the optimization of cyclic antimicrobial peptides via modulation of their backbone flexibility without loss of activity.

19.
Antimicrob Agents Chemother ; 60(9): 5427-36, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27381394

RESUMO

We used the fruit fly Drosophila melanogaster as a cost-effective in vivo model to evaluate the efficacy of novel antibacterial peptides and peptoids for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. A panel of peptides with known antibacterial activity in vitro and/or in vivo was tested in Drosophila Although most peptides and peptoids that were effective in vitro failed to rescue lethal effects of S. aureus infections in vivo, we found that two lantibiotics, nisin and NAI-107, rescued adult flies from fatal infections. Furthermore, NAI-107 rescued mortality of infection with the MRSA strain USA300 with an efficacy equivalent to that of vancomycin, a widely applied antibiotic for the treatment of serious MRSA infections. These results establish Drosophila as a useful model for in vivo drug evaluation of antibacterial peptides.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/veterinária , Sequência de Aminoácidos , Animais , Modelos Animais de Doenças , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/microbiologia , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Nisina/farmacologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/mortalidade , Análise de Sobrevida
20.
Ugeskr Laeger ; 178(13): V08150658, 2016 Mar 28.
Artigo em Dinamarquês | MEDLINE | ID: mdl-27045794

RESUMO

Avoiding exposure of extremities to cold combined with pharmacologic treatment usually suffice in the attempt to suppress the related symptoms of Raynaud's syndrome. This case report describes a severe case of Raynaud's syndrome affecting the lower extremities of a 16-year-old female. She was referred to a centre of vascular surgery with severe vasospasms of the feet. After failed attempts of pharmacologic treatment, a laparoscopic lumbar sympathectomy was performed with no complications and a slight reduction of symptoms three years post-surgically.


Assuntos
Doença de Raynaud/cirurgia , Simpatectomia , Adolescente , Feminino , Pé/patologia , Gânglios Espinais/cirurgia , Humanos , Laparoscopia/métodos , Plexo Lombossacral/cirurgia
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