751 resultados para lytic activity and cooperativity
Resumo:
Amphotericin B (AmB), an antifungal agent that presents a broad spectrum of activity, remains the gold standard in the antifungal therapy. However, sometimes the high level of toxicity forbids its clinical use. The aim of this work was to evaluate and compare the efficacy and toxicity in vitro of Fungizon™ (AmB-D) and two new different AmB formulations. Methods: three products were studied: Fungizon™, and two Fungizon™ /Lipofundin™ admixtures, which were diluted through two methods: in the first one, Fungizon™ was previously diluted with water for injection and then, in Lipofundin™ (AmB-DAL); the second method consisted of a primary dilution of AmB-D as a powder in the referred emulsion (AmB-DL). For the in vitro assay, two cell models were used: Red Blood Cells (RBC) from human donors and Candida tropicallis (Ct). The in vitro evaluation (K+ leakage, hemoglobin leakage and cell survival rate-CSR) was performed at four AmB concentrations (from 50 to 0.05mg.L-1). Results: The results showed that the action of AmB was not only concentration dependent, but also cellular type and vehicle kind dependent. At AmB concentrations of 50 mg.L-1, although the hemoglobin leakage for AmB-D was almost complete (99.51), for AmB-DAL and AmB-DL this value tended to zero. The p = 0.000 showed that AmB-D was significantly more hemolytic. Conclusion: The Fungizon™- Lipofundin™ admixtures seem to be the more valuable AmB carrier systems due to their best therapeutic index presented
Resumo:
Background: Currently, under half of the adolescents reach recommended daily levels of physical activity (PA). It is known that higher levels of PA lead to higher levels of cardiorespiratory fitness (CRF) and therefore, a health-related CRF criterion value could contribute to identify the target population for primary cardiovascular disease prevention. Therefore, the aim of this study was to explore the relation between PA levels and CRF factors in healthy adolescents. Methods: A cross-sectional exploratory study with healthy adolescents aged 12-18 years old was conducted. Socio-demographic and body composition data were collected using a questionnaire. PA level was scored with the Physical Activity Index (PAI) and CRF assessment included lung function (LF) measured with spirometry and exercise tolerance measured with Incremental Shuttle Walking Test (ISWT). According to PAI scores the sample was divided in two groups: 1 (sedentary, low and moderately active); 2 (vigorously active (VA)). Descriptive statistics were applied to characterise the sample. Independent sample t-tests assessed differences between groups and simple logistic regressions identified the predictors of being VA. Results: The study included 115 adolescents (14.63±1.70 years old; 56.52% female). Adolescents presented a normal body mass index=21.19±3.14 Kg.m-2) and LF (forced expiratory volume in the first second (FEV1)=105.58±12.73% of the predicted). Significant differences were found between groups in height (G1–163.44±8.01; G2–167±8.65; p=0.024), LF (FEV1/ forced vital capacity (FVC); G1–97.58±10.66; G2–94.04±8.04; p=0.049), ISWT distance (G1– 1089.81±214.04; G2–1173.60±191.86; p=0.038); heart rate (HR) at rest (G1– 84.61±13.68; G2–79.23±13.81; p=0.038), HR at the end of the best ISWT (G1– 124.71±37.57; G2–133.54±33.61; p=0.041) and percentage of the maximal HR achieved during ISWT (G1–63.09±19.03; G2–67.53±17.08; p=0.043). Simple logistic regressions showed that height (OR–1.054; 95%CI 1.006-1.104), ISWT distance (OR–1.002; 95%CI 1.000-1.004) and HR at rest (OR–0.971; 95%CI 0.945-0.999) were predictors of being VA. Conclusions: Results suggest that more physically active adolescents have a better CRF profile. The findings suggest that PA is important to adolescents’ health status and it should be encouraged since childhood. Clinical practice will benefit from the use of PAI, ISWT and HR findings, allowing physiotherapists to use it for prescribing exercise.
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PURPOSE: To evaluate quality of life in Portuguese patients with Systemic Lupus Erithematosus (SLE) and its correlation with disease activity and cumulative damage. METHODS: We included consecutive SLE patients, fulfilling the 1997 ACR Classification Criteria for SLE and followed at the Rheumatology Department of the University Hospital of Coimbra, Portugal at time of visit to the outpatient clinic. Quality of life was evaluated using the patient self-assessment questionnaire Medical Outcomes Survey Short Form-36 (SF-36) (validated Portuguese version). The consulting rheumatologist fulfilled the SLE associated indexes for cumulative damage (Systemic Lupus International Collaborating Clinics- Damage Index: SLICC/ACR-DI) and disease activity (Systemic Lupus Erythematosus Disease Activity Index: SLEDAI 2000). Correlation between SLEDAI and SLICC and SF-36 was tested with the Spearman Coefficient. Significant level considered was 0.05. RESULTS: The study included 133 SLE patients (90.2% female, mean age - 40.7 years, mean disease duration - 8.7 years). Most patients presented low disease activity (mean SLEDAI = 4.23) and limited cumulative damage (mean SLICC = 0.76). Despite that, SF-36 mean scores were below 70% in all eight domains of the index. Physical function domains showed lower scores than mental function domains. The QoL in this group of patients is significantly impaired when compared with the reference Portuguese population (p<0.05 in all domains). There was no correlation between clinical activity or cumulative damage and quality of life. CONCLUSION: QoL is significantly compromised in this group of SLE patients, but not related with disease activity or damage. These findings suggest that disease activity, cumulative damage and QoL are independent outcome measures and should all be used to assess the full impact of disease in SLE patients.
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Persistent forms of plasticity, such as long-term depression (LTD), are dependent on the interplay between activity-dependent synaptic tags and the capture of plasticity-related proteins. We propose that the synaptic tag represents a structural alteration that turns synapses permissive to change. We found that modulation of actin dynamics has different roles in the induction and maintenance of LTD. Inhibition of either actin depolymerisation or polymerization blocks LTD induction whereas only the inhibition of actin depolymerisation blocks LTD maintenance. Interestingly, we found that actin depolymerisation and CaMKII activation are involved in LTD synaptic-tagging and capture. Moreover, inhibition of actin polymerisation mimics the setting of a synaptic tag, in an activity-dependent manner, allowing the expression of LTD in non-stimulated synapses. Suspending synaptic activation also restricts the time window of synaptic capture, which can be restored by inhibiting actin polymerization. Our results support our hypothesis that modulation of the actin cytoskeleton provides an input-specific signal for synaptic protein capture.
Resumo:
Amphotericin B (AmB), an antifungal agent that presents a broad spectrum of activity, remains the gold standard in the antifungal therapy. However, sometimes the high level of toxicity forbids its clinical use. The aim of this work was to evaluate and compare the efficacy and toxicity in vitro of Fungizon™ (AmB-D) and two new different AmB formulations. Methods: three products were studied: Fungizon™, and two Fungizon™ /Lipofundin™ admixtures, which were diluted through two methods: in the first one, Fungizon™ was previously diluted with water for injection and then, in Lipofundin™ (AmB-DAL); the second method consisted of a primary dilution of AmB-D as a powder in the referred emulsion (AmB-DL). For the in vitro assay, two cell models were used: Red Blood Cells (RBC) from human donors and Candida tropicallis (Ct). The in vitro evaluation (K+ leakage, hemoglobin leakage and cell survival rate-CSR) was performed at four AmB concentrations (from 50 to 0.05mg.L-1). Results: The results showed that the action of AmB was not only concentration dependent, but also cellular type and vehicle kind dependent. At AmB concentrations of 50 mg.L-1, although the hemoglobin leakage for AmB-D was almost complete (99.51), for AmB-DAL and AmB-DL this value tended to zero. The p = 0.000 showed that AmB-D was significantly more hemolytic. Conclusion: The Fungizon™- Lipofundin™ admixtures seem to be the more valuable AmB carrier systems due to their best therapeutic index presented
Resumo:
In the Pacific oyster, spermatozoa are characterized by a remarkably long movement phase (i.e., over 24 h) sustained by a capacity to maintain intracellular ATP level. To gain information on oxidative phosphorylation (OXPHOS) functionality during the motility phase of Pacific oyster spermatozoa, we studied 1) changes in spermatozoal mitochondrial activity, that is, mitochondrial membrane potential (MMP), and intracellular ATP content in relation to motion parameters and 2) the involvement of OXPHOS for spermatozoal movement using carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The percentage of motile spermatozoa decreased over a 24 h movement period. MMP increased steadily during the first 9 h of the movement phase and was subsequently maintained at a constant level. Conversely, spermatozoal ATP content decreased steadily during the first 9 h postactivation and was maintained at this level during the following hours of the movement phase. When OXPHOS was decoupled by CCCP, the movement of spermatozoa was maintained 2 h and totally stopped after 4 h of incubation, whereas spermatozoa were still motile in the control after 4 h. Our results suggest that the ATP sustaining flagellar movement of spermatozoa may partially originate from glycolysis or from mobilization of stored ATP or from potential phosphagens during the first 2 h of movement as deduced by the decoupling by CCCP of OXPHOS. However, OXPHOS is required to sustain the long motility phase of Pacific oyster spermatozoa. In addition, spermatozoa may hydrolyze intracellular ATP content during the early part of the movement phase, stimulating mitochondrial activity. This stimulation seems to be involved in sustaining a high ATP level until the end of the motility phase.
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Receiving personalised feedback on body mass index and other health risk indicators may prompt behaviour change. Few studies have investigated men’s reactions to receiving objective feedback on such measures and detailed information on physical activity and sedentary time. The aim of my research was to understand the meanings different forms of objective feedback have for overweight/obese men, and to explore whether these varied between groups. Participants took part in Football Fans in Training, a gender-sensitised, weight loss programme delivered via Scottish Professional Football Clubs. Semi-structured interviews were conducted with 28 men, purposively sampled from four clubs to investigate the experiences of men who achieved and did not achieve their 5% weight loss target. Data were analysed using the principles of thematic analysis and interpreted through Self-Determination Theory and sociological understandings of masculinity. Several factors were vital in supporting a ‘motivational climate’ in which men could feel ‘at ease’ and adopt self-regulation strategies: the ‘place’ was described as motivating, whereas the ‘people’ (other men ‘like them’; fieldwork staff; community coaches) provided supportive and facilitative roles. Men who achieved greater weight loss were more likely to describe being motivated as a consequence of receiving information on their objective health risk indicators. They continued using self-monitoring technologies after the programme as it was enjoyable; or they had redefined themselves by integrating new-found activities into their lives and no longer relied on external technologies/feedback. They were more likely to see post-programme feedback as confirmation of success, so long as they could fully interpret the information. Men who did not achieve their 5% weight loss reported no longer being motivated to continue their activity levels or self-monitor them with a pedometer. Social support within the programme appeared more important. These men were also less positive about objective post-programme feedback which confirmed their lack of success and had less utility as a motivational tool. Providing different forms of objective feedback to men within an environment that has intrinsic value (e.g. football club setting) and congruent with common cultural constructions of masculinity, appears more conducive to health behaviour change.
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In this study, Dicentrarchus labrax encephalitis virus (DIEV), which causes sea bass encephalitis, was propagated in cell culture, thus allowing study of its lytic cycle, DIEV infection of mammalian and fish cells induced different patterns of expression of capsid proteins, which were assembled as virus-like particles, accumulating in the cytoplasm either as diffuse masses or in vesicles, as shown by electron microscopy, These particles correspond to virions, as shown by their ability to induce Secondary infection, Fish cells proved to be more permissive for DIEV than mammalian cells, although virus yield remained low, RNA analysis of infected sea bass cells revealed DIEV RNA3, in addition to genomic RNA1 and RNA2, and the presence of the RNA;! minus strand, thus demonstrating the replication of the DIEV genome, In addition, DIEV RNA-dependent RNA polymerase was associated with mature virions even after purification by a CsCl gradient, but it was dissociated when capsids were destabilized, In addition to providing more information about the relatedness of DIEV to the members of the family Nodaviridae, this study shows that fish nodaviruses may not be able to infect as wide a variety of cells as insect nodaviruses can.
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Background: Globally, chronic B viral hepatitis (HBV) is a major health problem. Obesity is a common problem among patients with HBV. Several studies have reported that obesity is an important risk factor that alters immune system response in individuals with no underlying cause of liver disease. However, there is a strong association between BMI and the human immune system among HBV patients. Objective: This study was to examine the correlation between body mass index, serum alanine aminotransferase activity (ALT) and immunologic response in obese hepatitis B patients. Material and methods: One hundred fifty male patients with chronic hepatitis B virus, their age ranged from 30 to 45 (38.64 ± 7.12) years and their BMI ranged from 30-35 kg/m2. All Subjects were included in two groups: The first group received weight reduction program in the form of treadmill aerobic exercises in addition to diet control whereas the second group received no therapeutic intervention. Parameters of serum alanine aminotransferase (ALT), CD3, CD4 and CD8 were quantified; Leukocyte, differential counts and body mass index (BMI) were measured before and after 3 months at the end of the study. Results: There was a 24.7%, 36.8%, 30.8%, 40.7%, 28.6%, 25.9%, 33.3% and 14.3 % reduction in mean values of alanine aminotransferase (ALT), white blood cells, total neutrophil count, monocytes, CD3, CD4 ,CD8 and BMI respectively in group (A) at the end of the study. In addition, there were significant differences between mean levels of the investigated parameters in groups. Conclusion: Based on our findings, weight loss modulates serum alanine aminotransferase and immune system parameters of patients with hepatitis B virus infection.
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Helicobacter pylori is a bacterium recognized as the major cause of chronic gastritis and peptic ulcers. Infection by H. pylori induces inflammatory responses and pathological changes in the gastric microenvironment. The host Keywords: immune cells (especially neutrophils) release inflammatory mediators and large 5-methoxy-3,4-dehydroxanthomegnin amounts of reactive oxygen species (ROS), which are associated with an increased Helicobacter pyloririsk of developing gastric cancer. In this study, we evaluated the anti-H. pylori and oxidative burst antioxidantactivitiesofa1,4-naphthoquinone-5-methoxy-3,4-dehydroxanthomegnin. Paepalanthus latipes The antimicrobial activity was assessed using a spectrophotometric microdilution technique, and antioxidant activity was assessed by noting the effect of 5-methoxy3,4-dehydroxanthomegnin on the neutrophil oxidative burst using luminol-and lucigenin-amplified chemiluminescence. The results showed that 5-methoxy-3,4dehydroxanthomegnin is a potent anti-H. pylori compound (MIC 64 µg/mL and MBC 128 µg/mL) and a strong antioxidant. 5-Methoxy-3,4-dehydroxanthomegnin decreased luminol- and lucigenin-amplified chemiluminescence, with ED50 values of 1.58±0.09 µg/mL and 5.4±0.15 µg/mL, respectively, reflecting an inhibitory effect on the oxidative burst. These results indicate that 5-methoxy-3,4-dehydroxanthomegnin is a promising compound for the prevention and treatment of diseases caused by H. pylori infection, such as gastritis, peptic ulceration, and gastric cancer, because reactive oxygen intermediates are involved in the pathogenesis of gastric mucosal injury induced by H. pylori infections.
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The polar hydroethanolic extract from Selaginella sellowii (SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis.
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In the first half of this thesis, a new robotic instrument called a scanning impedance probe is presented that can acquire electrochemical impedance spectra in automated fashion from hundreds of thin film microelectrodes with systematically varied properties. Results from this instrument are presented for three catalyst compositions that are commonly considered for use in state-of-the-art solid oxide fuel cell cathodes. For (La0.8Sr0.2)0.95MnO3+δ (LSM), the impedance spectra are well fit by a through-the-film reaction pathway. Transport rates are extracted, and the surface activity towards oxygen reduction is found to be correlated with the number of exposed grain boundary sites, suggesting that grain boundaries are more surface-active than grains. For La0.5Sr0.5CoO3-δ (LSC), the surface activity degrades ~50x initially and then stabilizes at a comparable activity to that of previously measured Ba0.5Sr0.5Co0.8Fe0.2O3-δ films. For Sr0.06Nb0.06Bi1.87O3 (SNB), an example of a doped bismuth oxide, the activity of the metal-SNB boundary is measured.
In the second half of this thesis, SrCo0.9Nb0.1O3-δ is selected as a case study of perovskites containing Sr and Co, which are the most active oxygen reduction catalysts known. Several bulk properties are measured, and synchrotron data are presented that provide strong evidence of substantial cobalt-oxygen covalency at high temperatures. This covalent bonding may be the underlying source of the high surface activity.