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 JovemRESUMO
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/genéticaRESUMO
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 , HumanosRESUMO
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 (=âCEUS 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 (93.1â%) 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 (nâ=â299), the highest sensitivity for the diagnosis of HCC was achieved with the CEUS algorithm ESCULAP (94.2â%) and CEUS on-site (90.9â%). The lowest sensitivity was reached with the CEUS LI-RADS algorithm (64â%; pâ<â0.001). However, the specificity of CEUS LI-RADS (78.9â%) was superior to that of ESCULAP (50.9â%) and CEUS on-site (64.9â%; pâ<â0.001). At the same time, the negative predictive value (NPV) of CEUS LI-RADS was significantly inferior to that of ESCULAP (34.1â% vs. 67.4â%; pâ<â0.001) and CEUS on-site (62.7â%; pâ<â0.001). The positive predictive values of all modalities were high (around 90â%), 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 , UltrassonografiaRESUMO
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 fármacosRESUMO
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 XRESUMO
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 fármacosRESUMO
As drug-resistant pathogens continue to emerge, combination therapy will increasingly be relied upon to treat infections and to help combat further development of multidrug resistance. At present a dichotomy exists between clinical practice, which favors therapeutically synergistic combinations, and the scientific model emerging from in vitro experimental work, which maintains that this interaction provides greater selective pressure toward resistance development than other interaction types. We sought to extend the current paradigm, based on work below or near minimum inhibitory concentration levels, to reflect drug concentrations more likely to be encountered during treatment. We performed a series of adaptive evolution experiments using Staphylococcus aureus. Interestingly, no relationship between drug interaction type and resistance evolution was found as resistance increased significantly beyond wild-type levels. All drug combinations, irrespective of interaction types, effectively limited resistance evolution compared with monotreatment. Cross-resistance and collateral sensitivity were found to be important factors in the extent of resistance evolution toward a combination. Comparative genomic analyses revealed that resistance to drug combinations was mediated largely by mutations in the same genes as single-drug-evolved lineages highlighting the importance of the component drugs in determining the rate of resistance evolution. Results of this work suggest that the mechanisms of resistance to constituent drugs should be the focus of future resistance evolution work.
Assuntos
Farmacorresistência Bacteriana/genética , Evolução Molecular , Infecções Estafilocócicas/genética , Staphylococcus aureus/genética , Combinação de Medicamentos , Humanos , Mutação , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidadeRESUMO
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 SobrevidaRESUMO
Multiple strains of Acinetobacter baumannii have developed multidrug resistance (MDR), leaving colistin as the only effective treatment. The cecropin-α-melittin hybrid BP100 (KKLFKKILKYL-NH2) and its analogs have previously shown activity against a wide array of plant and human pathogens. In this study, we investigated the in vitro antibacterial activities of 18 BP100 analogs (four known and 14 new) against the MDR A. baumannii strain ATCC BAA-1605, as well as against a number of other clinically relevant human pathogens. Selected peptides were further evaluated against strains of A. baumannii that acquired resistance to colistin due to mutations of the lpxC, lpxD, pmrA, and pmrB genes. The novel analogue BP214 showed antimicrobial activity at 1 to 2 µM and a hemolytic 50% effective concentration (EC50) of >150 µM. The lower activity of its enantiomer suggests a dual, specific and nonspecific mode of action. Interestingly, colistin behaved antagonistically to BP214 when pmrAB and lpxC mutants were challenged.
Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Oligopeptídeos/farmacologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/metabolismo , Aciltransferases/genética , Aciltransferases/metabolismo , Amidoidrolases/genética , Amidoidrolases/metabolismo , Sequência de Aminoácidos , Antibacterianos/síntese química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Colistina/farmacologia , Farmacorresistência Bacteriana/genética , Eritrócitos/efeitos dos fármacos , Expressão Gênica , Hemólise/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mutação , Oligopeptídeos/síntese química , Técnicas de Síntese em Fase Sólida , Relação Estrutura-Atividade , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
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 , RefeiçõesRESUMO
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/métodosRESUMO
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.
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.
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 , FenilalaninaRESUMO
BACKGROUND: Sulphadoxine-pyrimethamine (SP) and chloroquine (CQ) have been used in treatment of falciparum and vivax malaria in Nepal. Recently, resistance to both drugs have necessitated a change towards artemisinin combination therapy (ACT) against Plasmodium falciparum in highly endemic areas. However, SP is still used against P. falciparum infections in low endemic areas while CQ is used in suspected cases in areas with lack of diagnostic facilities. This study examines the prevalence of molecular markers of CQ and SP resistance in P. falciparum and Plasmodium vivax to determine if high levels of in vivo resistance are reflected at molecular level as well. METHODS: Finger prick blood samples (n=189) were collected from malaria positive patients from two high endemic districts and analysed for single nucleotide polymorphisms (SNPs) in the resistance related genes of P. falciparum and P. vivax for CQ (Pfcrt, Pfmdr1, Pvmdr1) and SP (Pfdhfr, Pfdhps, Pvdhfr), using various PCR-based methods. RESULTS AND DISCUSSION: Positive P. vivax and P. falciparum infections were identified by PCR in 92 and 41 samples respectively. However, some of these were negative in subsequent PCRs. Based on a few P. falciparum samples, the molecular level of CQ resistance in P. falciparum was high since nearly all parasites had the Pfcrt mutant haplotypes CVIET (55%) or SVMNT (42%), though frequency of the Pfmdr1 wild type haplotype was relatively low (35%). Molecular level of SP resistance in P. falciparum was found to be high. The most prevalent Pfdhfr haplotype was double mutant CNRNI (91%), while frequency of Pfdhps double mutant SGEAA and AGEAA were 38% and 33% respectively. Combined, the frequency of quadruple mutations (CNRNI-SGEAA/AGEAA) was 63%. Based on P. vivax samples, low CQ and SP resistance were most likely due to low prevalence of Pvmdr1 Y976F mutation (5%) and absence of triple/quadruple mutations in Pvdhfr. CONCLUSIONS: Based on the limited number of samples, prevalence of CQ and SP resistance at molecular levels in the population in the study area were determined as high in P. falciparum and low in P. vivax. Therefore, CQ could still be used in the treatment of P. vivax infections, but this remains to be tested in vivo while the change to ACT for P. falciparum seems justified.
Assuntos
Antimaláricos/farmacologia , Resistência a Medicamentos , Malária Falciparum/tratamento farmacológico , Malária Vivax/tratamento farmacológico , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Polimorfismo de Nucleotídeo Único , Proteínas de Protozoários/genética , Antimaláricos/uso terapêutico , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Cloroquina/farmacologia , Cloroquina/uso terapêutico , Combinação de Medicamentos , Humanos , Malária Falciparum/genética , Malária Falciparum/parasitologia , Malária Vivax/genética , Malária Vivax/parasitologia , Nepal , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Plasmodium vivax/efeitos dos fármacos , Plasmodium vivax/genética , Reação em Cadeia da Polimerase , Pirimetamina/farmacologia , Pirimetamina/uso terapêutico , Sulfadoxina/farmacologia , Sulfadoxina/uso terapêuticoRESUMO
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/químicaRESUMO
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 XRESUMO
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.