Dietary tryptophan deficiency and its supplementation compromises inflammatory mechanisms and disease resistance in a teleost fish

Tryptophan participates on several physiological mechanisms of the neuroendocrine-immune network and plays a critical role in macrophages and lymphocytes function. This study intended to evaluate the modulatory effects of dietary tryptophan on the European seabass (Dicentrarchus labrax) immune status, inflammatory response and disease resistance to Photobacterium damselae piscicida. A tryptophan deficient diet (NTRP); a control diet (CTRL); and two other diets supplemented with tryptophan at 0.13% (TRP13) and 0.17% (TRP17) of feed weight were formulated. Fish were sampled at 2 and 4 weeks of feeding and the remaining were i.p. injected with Phdp (3 × 10⁶ cfu/fish) at 4 weeks and the inflammatory response (at 4, 24, 48 and 72 hours post-infection) as well as survival were evaluated. Results suggest that fish immune status was not altered in a tryptophan deficient scenario whereas in response to an inflammatory insult, plasma cortisol levels increased and the immune cell response was compromised, which translated in a lower disease resistance. When dietary tryptophan was offered 30% above its requirement level, plasma cortisol increased and, in response to bacterial infection, a decrease in lymphocytes, monocytes/macrophages and several immune-related genes was observed, also compromising at some degree fish disease resistance.

Physiopathological responses of sole (Solea senegalensis) subjected to bacterial infection and handling stress after probiotic treatment with autochthonous bacteria

This study aimed to evaluate the protective effects of four autochthonous bacteria isolated from juvenile sole (Solea senegalensis) intestine as dietary probiotic supplement against bacterial pathogen infection and handling/transport stressors. Growth performance and immune responses were evaluated after 85 days of feeding trial. Sole (IBW = 16.07 ± 0.11 g) were fed six experimental diets, a control diet (CTRL, without the dietary probiotic supplementation), and five diets supplemented with probiotic bacteria: PB1 (Shewanella hafniensis), PB2 (Enterococcus raffinosus), PB3 (Shewanella hafniensis + Arthrobacter soli), PB4 (Pseudomonas protegens + Arthrobacter soli) and PB5 (Shewanella hafniensis + Arthrobacter soli + Enterococcus raffinosus). All bacteria were selected based on their in vitro antimicrobial activity. After the growth trial, fish were submitted to a stress factor (transport) and then each dietary group was divided in two additional groups: non-infected (placebo) and infected with Photobacterium damselae subsp. piscicida. Immune and antioxidant responses were evaluated at day 10 post-infection. In infection trial A, fish were infected on the same day of transport, whereas in trial B fish were infected after a 7-day recovery from the transport stress. At the end of the feeding trial, fish fed with PB2 and PB4 showed lower final body weight when compared with the other dietary groups. Respiratory burst activity and nitric oxide production were not affected by probiotic supplementation. Fish fed with PB5 presented lower peroxidase activity compared to CTRL. Lysozyme and alternative complement pathway activity (ACH50) showed no significant differences between treatments. The innate immune responses were significantly affected after handling stress and bacterial infection. In trial A, the ACH50 levels of infected fish were significantly lower than the placebo groups. On the other hand, in trial B fish infected with Pdp demonstrated higher ACH50 levels when compared to placebos. Peroxidase levels were strongly modulated by bacterial infection and handling stress. In trials A and B, infection had a clear downgrade effect in peroxidase levels. Lipid peroxidation, catalase, glutathione S-transferase and glutathione reductase were altered by both bacterial infection and transport. Overall, dietary probiotic supplementation did not influence growth performance of sole. The immune and oxidative defenses of sole responded differently to infection depending on the probiotic and the synergy between pathogen infection and transport.

Smartphone based monitoring system for long-term sleep assessment

The diagnosis of sleep disorders, highly prevalent in Western countries, typically involves sophisticated procedures and equipment that are highly intrusive to the patient. The high processing capabilities and storage capacity of current portable devices, together with a big range of available sensors, many of them with wireless capabilities, create new opportunities and change the paradigms in sleep studies. In this work, a smartphone based sleep monitoring system is presented along with the details of the hardware, software and algorithm implementation. The aim of this system is to provide a way for subjects, with no pre-diagnosed sleep disorders, to monitor their sleep habits, and on the initial screening of abnormal sleep patterns.

Sleep and wakefulness state detection in nocturnal actigraphy based on movement information

Wrist actigraphy (ACT) is a low-cost and well-established technique for long-term monitoring of human activity. It has a special relevance in sleep studies, where its noninvasive nature makes it a valuable tool for behavioral characterization and for the detection and diagnosis of some sleep disorders. The traditional sleep/wakefulness state estimation algorithms from the nocturnal ACT data are unbalanced from a sensitivity and specificity points of view since they tend to overestimate sleep state, with severe consequences from a diagnosis point of view. They usually maximize the overall accuracy that does not take into account the highly unbalanced state distribution. In this paper, a method is proposed to appropriately deal with this unbalanced problem, achieving similar sensitivity and specificity scores in the state estimation process. The proposed method combines two linear discriminant classifiers, trained with two different criteria involving movement detection to generate a first state estimate. This result is then refined by a Hidden Markov Model-based algorithm. The global accuracy, the sensitivity, and the specificity of the method are 77.8%, 75.6%, and 81.6%, respectively, performing better than the tested algorithms. If the performance is assessed only for movement periods, this improvement is even higher.

An actigraphy heterogeneous mixture model for sleep assessment

Wrist actigraphy is a well established procedure to monitor human activity. Among other areas, it has a special relevance in sleep studies where its lightweight and non-intrusive nature make it a valuable tool to access the circadian cycle. While there are several methods to extract information from the data, the differentiation between sleep and wakefulness states is still an open discussion. In this paper, the characteristics of the movements in the different states are assumed to be intrinsically different. These differences are not simply related with magnitude and movement counting, but due to real differences on the statistical distributions describing the actigraphy data. Thus it is possible to refine the discrimination level when detecting these states. The proposed methodology to characterize the actigraphy data is based on a mixture of three canonical distributions; i)Exponential, ii)Rayleigh and iii)Gaussian. It is shown that the weights and parameters estimated in each state are organized into almost separable clusters on the feature space. This suggests the ability of the method to discriminate these states based only on the movements recorded on actigraphy data.

Developmental exposure to diuron causes splenotoxicity in male Sprague-Dawley rat pups

This study investigated whether perinatal exposure to diuron [3-(3,4-dichlorophenyl)-1-1-dimethylurea] might exert adverse effects on rat lymphoid organs. Pregnant Sprague-Dawley (SD) rats were exposed to diuron at 500, 750 or 1250 ppm in the diet from gestational days (GD) 12-21 and during lactation. At postnatal day (PND) 42, male pups were euthanized and thymus, spleen, mesenteric lymph node and femur were collected for histopathological analysis. Food consumption and body weight gain were significantly reduced in dams exposed to 1250 ppm during gestation period. Also, Diuron at 750 and 1250 ppm produced: (1) increased relative spleen weight associated histologically with severe congestion in red pulp, (2) enhanced extramedullary hematopoiesis and hemosiderosis as well as (3) depletion of lymphoid follicles in white pulp. Flow cytometric analysis revealed a significant reduction in B lymphocytes (CD45RA+) in male pups but T lymphocytes (CD4+, CD8+ and CD4+/CD8+) were not markedly affected. Thus, data suggest that Diuron-induced maternal toxicity in dams exposed to high dose and perinatal exposure to this herbicide produced spleen toxicity as evidenced by a reduction in B lymphocyte number in male SD pups.

Prevention of experimental diabetes by Uncaria tomentosa extract: Th2 polarization, regulatory T cell preservation or both?

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria tomentosa (Willd.) DC (Rubiaceae) is a species native to the Amazon rainforest and surrounding tropical areas that is endowed with immunomodulatory properties and widely used around the world. In this study we investigated the immunomodulatory potential of Uncaria tomentosa (UT) aqueous-ethanol extract on the progression of immune-mediated diabetes.

MATERIALS AND METHODS

C57BL/6 male mice were injected with MLDS (40 mg/kg) and orally treated with UT at 10-400mg/kg during 21 days. Control groups received MLDS alone or the respective dilution vehicle. Pancreatic mononuclear infiltrate and β-cell insulin content were analyzed by HE and immunohistochemical staining, respectively, and measured by digital morphometry. Lymphocyte immunophenotyping and cytokine production were determined by flow cytometry analysis.

RESULTS

Treating the animals with 50-400mg/kg of UT caused a significant reduction in the glycemic levels, as well as in the incidence of diabetes. The morphometric analysis of insulitis revealed a clear protective effect. Animals treated with UT at 400mg/kg presented a higher number of intact islets and a significant inhibition of destructive insulitis. Furthermore, a significant protection against the loss of insulin-secreting presented β-cells was achieved, as observed by a careful immunohistochemical evaluation. The phenotypic analysis indicated that the groups treated with higher doses (100-400mg/kg) presented CD4(+) and CD8(+) T-cell values similar to those observed in healthy animals. These same higher doses also increased the number of CD4(+)CD25(+)Foxp3(+) regulatory T-cells. Moreover, the extract modulated the production of Th1 and Th2, with increased levels of IL-4 and IL-5.

CONCLUSIONS

The extract was effective to prevent the progression of immune-mediated diabetes by distinct pathways.

Uncaria tomentosa aqueous-ethanol extract triggers an immunomodulation toward a Th2 cytokine profile

Uncaria tomentosa (Willd.) DC (Rubiaceae) is a large woody vine that is native to the Amazon and Central American rainforests and is used widely in traditional medicine for its immunomodulatory and antiinflammatory activities. The present work used in vivo immunotoxic and in vitro immunomodulatory experiments to investigate the effects of a pentacyclic oxindole alkaloid extract from U. tomentosa bark on lymphocyte phenotype, Th1/Th2 cytokine production, cellular proliferation and cytotoxicity. For the in vivo immunotoxicity testing, BALB/c male mice were treated once a day with 125, 500 or 1250 mg/kg of U. tomentosa extract for 28 days. For the in vitro protocol, lymphocytes were cultured with 10-500 μg/mg of the extract for 48 h. The extract increased the cellularity of splenic white pulp and the thymic medulla and increased the number of T helper lymphocytes and B lymphocytes. Also, a large stimulatory effect on lymphocyte viability was observed. However, mitogen-induced T lymphocyte proliferation was significantly inhibited at higher concentrations of U. tomentosa extract. Furthermore, an immunological polarization toward a Th2 cytokine profile was observed. These results suggest that the U. tomentosa aqueous-ethanol extract was not immunotoxic to mice and was able to modulate distinct patterns of the immune system in a dose-dependent manner.

Diuron exposure induces systemic and organ-specific toxicity following acute and sub-chronic exposure in male Wistar rats

Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is a substitute urea herbicide widely used on agricultural crops with potential mutagenic, teratogenic, reproductive and carcinogenic effects. Nonetheless, its toxic potential on the immune system needs a detailed assessment. Thus, in order to evaluate the adverse effect of this herbicide on lymphohematopoietic organs and macrophage activity, male Wistar rats were orally treated with Diuron at 125, 1250 and 2500 ppm for 14, 28 or 90 days. General signs of toxicity were observed in Diuron-treated groups (1250 and 2500 ppm), including reduced food intake and body weight gain, as well as higher relative weights for spleen, kidneys and liver (28 and 90-day toxicity studies) and elevated serum levels of ALT, albumin, total protein, creatinine and urea (28-day toxicity study). Diuron exposure caused a severe depletion of splenic white pulp compartments and cellularity, followed by a decreased number of CD4(+) T lymphocytes, increased extramedullary hematopoiesis and deposition of hemosiderin in red pulp. Despite alteration in macrophage spreading, the macrophagic activity was not significantly affected by the herbicide. Under these experimental conditions, the results suggest that Diuron exerts systemic and target-organ toxicity, mainly at higher concentration.

Automatic annotation of actigraphy data for sleep disorders diagnosis purposes

The diagnosis of Sleep disorders, highly prevalent in the western countries, typically involves sophisticated procedures and equipments that are intrusive to the patient. Wrist actigraphy, on the contrary, is a non-invasive and low cost solution to gather data which can provide valuable information in the diagnosis of these disorders. The acquired data may be used to infer the Sleep/Wakefulness (SW) state of the patient during the circadian cycle and detect abnormal behavioral patterns associated with these disorders. In this paper a classifier based on Autoregressive (AR) model coefficients, among other features, is proposed to estimate the SW state. The real data, acquired from 23 healthy subjects during fourteen days each, was segmented by expert medical personal with the help of complementary information such as light intensity and Sleep e-Diary information. Monte Carlo tests with a Leave-One-Out Cross Validation (LOOCV) strategy were used to assess the performance of the classifier which achieves an accuracy of 96%.

Optimization strategies for metabolic networks

Background

The increasing availability of models and data for metabolic networks poses new challenges in what concerns optimization for biological systems. Due to the high level of complexity and uncertainty associated to these networks the suggested models often lack detail and liability, required to determine the proper optimization strategies. A possible approach to overcome this limitation is the combination of both kinetic and stoichiometric models. In this paper three control optimization methods, with different levels of complexity and assuming various degrees of process information, are presented and their results compared using a prototype network.

Results

The results obtained show that Bi-Level optimization lead to a good approximation of the optimum attainable with the full information on the original network. Furthermore, using Pontryagin's Maximum Principle it is shown that the optimal control for the network in question, can only assume values on the extremes of the interval of its possible values.

Conclusions

It is shown that, for a class of networks in which the product that favors cell growth competes with the desired product yield, the optimal control that explores this trade-off assumes only extreme values. The proposed Bi-Level optimization led to a good approximation of the original network, allowing to overcome the limitation on the available information, often present in metabolic network models. Although the prototype network considered, it is stressed that the results obtained concern methods, and provide guidelines that are valid in a wider context.

Decreased production of TNF-alpha by lymph node cells indicates experimental autoimmune encephalomyelitis remission in Lewis rats

Experimental autoimmune encephalomyelitis (EAE) is mediated by CD4+ Th1 cells that mainly secrete IFN-gamma and TNF-alpha, important cytokines in the pathophysiology of the disease. Spontaneous remission is, in part, attributed to the down regulation of IFN-gamma and TNF-alpha by TGF-beta. In the current paper, we compared weight, histopathology and immunological parameters during the acute and recovery phases of EAE to establish the best biomarker for clinical remission. Female Lewis rats were immunised with myelin basic protein (MBP) emulsified with complete Freund's adjuvant. Animals were evaluated daily for clinical score and weight prior to euthanisation. All immunised animals developed the expected characteristics of EAE during the acute phase, including significant weight loss and high clinical scores. Disease remission was associated with a significant reduction in clinical scores, although immunised rats did not regain their initial weight values. Brain inflammatory infiltrates were higher during the acute phase. During the remission phase, anti-myelin antibody levels increased, whereas TNF-alpha and IFN-gamma production by lymph node cells cultured with MBP or concanavalin A, respectively, decreased. The most significant difference observed between the acute and recovery phases was in the induction of TNF-alpha levels in MBP-stimulated cultures. Therefore, the in vitro production of this cytokine could be used as a biomarker for EAE remission.

Statistical characterization of actigraphy data during sleep and wakefulness states

Human activity can be measured with actimetry sensors used by the subjects in several locations such as the wrists or legs. Actigraphy data is used in different contexts such as sports training or tele-medicine monitoring. In the diagnosis of sleep disorders, the actimetry sensor, which is basically a 3D axis accelerometer, is used by the patient in the non dominant wrist typically during an entire week. In this paper the actigraphy data is described by a weighted mixture of two distributions where the weight evolves along the day according to the patient circadian cycle. Thus, one of the distributions is mainly associated with the wakefulness state while the other is associated with the sleep state. Actigraphy data, acquired from 20 healthy patients and manually segmented by trained technicians, is used to characterize the acceleration magnitude during sleep and wakefulness states. Several mixture combinations are tested and statistically validated with conformity measures. It is shown that both distributions can co-exist at a certain time with varying importance along the circadian cycle.

Toxicity of beta-amyloid in HEK293 cells expressing NR1/NR2A or NR1/NR2B N-methyl-D-aspartate receptor subunits

Neurotoxicity induced by beta-amyloid peptide (Abeta) involves glutamate toxicity, resulting from overactivation of N-methyl-D-aspartate (NMDA) receptors and elevation of intracellular calcium. However, the heterogeneity of the NMDA receptors, frequently composed of NR1 and NR2A-D subunits, has been less studied. Thus, we determined the contribution of NMDA receptor subtypes on Abeta(1-40) toxicity in HEK293 cells transiently expressing NR1/NR2A or NR1/NR2B subunits. Analysis of lactate dehydrogenase (LDH) release and trypan blue exclusion revealed an increase in Abeta(1-40) toxicity upon NR1/NR2A expression, compared to NR1/NR2B, indicating loss of plasma membrane integrity. Furthermore, Abeta(1-40) decreased intracellular ATP in cells expressing NR1/NR2A. MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate), a noncompetitive NMDA receptor antagonist, partially prevented the decrease in cell viability and the energy impairment. These differences were not accounted for by the activation of caspases 2, 3, 8 and 9 or calpains or by DNA fragmentation, excluding the hypothesis of apoptosis. Functional NR1/NR2A and NR1/NR2B receptor subtypes were further evidenced by single-cell calcium imaging. Stimulation of NR1/NR2A receptors with NMDA/glycine revealed an increase in intracellular calcium in cells pre-exposed to Abeta(1-40). Opposite effects were observed upon activation of NR1/NR2B receptors. These results suggest that NR1/NR2A-composed NMDA receptors mediate necrotic cell death in HEK293 cells exposed to Abeta(1-40) through changes in calcium homeostasis.

[Obesity and quality of life]

Obesity is considered one of the most relevant health problems of modern societies, as it constitutes a predominant risk factor in the development of various other diseases. The negative impact of obesity on the quality of life of individuals has been the subject of diverse research. The results of a test carried out at Gothenburg University in Sweden suggest that severe obesity is a debilitating factor both for health and psychosocial functioning. Research carried out in Madrid permitted identification of a profile of obese patients with impaired quality of life, which has enabled prophylactic intervention or early treatment of these cases to be considered. The results of a study carried out in the USA propose that pain would appear to be directly related with quality of life and could be considered a covariant of obesity, and should therefore be taken into account in obesity treatments. A study carried out in Oxford concluded that obese subjects or subjects with another chronic disease presented a deterioration in physical wellbeing, however only subjects with another chronic disease (without associated obesity) presented a deterioration in psychological wellbeing. The majority of studies suggest the negative influence of obesity and overweight on health and psychosocial functioning, however it is not possible to clearly define a linear relation between obesity and diminished quality of life.

The relationship between body mass index and educational level in young Portuguese males: 1995 and 1999 cohorts

INTRODUCTION

Over the last decades, a progressive increase in height and weight has been observed throughout Europe. Increase in weight has been more marked however, with a resulting increase in overweight and obesity prevalence. RESULTS published have analyzed the relationship between body mass index (BMI) and educational level. Most studies indicate an inverse relationship between BMI and educational level in developed countries.

OBJECTIVE

This study's main objective was to evaluate the relationship between BMI and educational level (years of schooling) in young Portuguese males in 1995 and 1999.

METHODS

Transverse study of data (BMI and years of schooling) from the military inspection records of virtually the entire Portuguese male population with an average age of 20 years, examined in 1995 and 1999, totaling 81 363 and 71 254, respectively. Four classes of BMI (<20, 20-24.9, 25-29.9 and > or =30 kg/m2) and four schooling levels (<5, 5-9, 10-12, and >12 years) were considered. We applied the chi2 test for associations between BMI and educational level and the odds ratio to quantify categorical variables. The significance level was 5%.

RESULTS

In 1995, 15.2% were overweight (BMI> or =25 years), increasing to 20.8% in 1999. The percentage of obesity (BMI> or =30 years) was 1.4% in 1995 and 2.2% in 1999. The percentage of overweight and obesity increased directly in line with the increase in educational level, both in 1995 and 1999. In 1995, the percentage of subjects with obesity according to years of schooling was as follows: <5 years--1.4%; 5-9 years--1.4%; 10-12 years--1.5% and >12 years--1.7%. In 1999, the results were as follows: <5 years--1.4%; 5-9 years--2.2%; 10-12 years--2.8% and >12 years--3.2%.

CONCLUSIONS

We can conclude that the prevalence of overweight and obesity in young male Portuguese increased in the last decade and that, unlike most developed countries, the higher the level of education, the greater the percentage of overweight and obesity, both in 1995 and 1999.

Risk factors for typhlitis

A case-control study was undertaken to identify risk factors for typhlitis in patients with hematological malignancies. A data base file with a total of 410 episodes of fever and neutropenia in patients cared for between May 1987 and 1996 was reviewed. Typhlitis was defined as a symptom complex of fever, intense abdominal pain and tenderness in the presence of neutropenia. Five cases of typhlitis were identified. Three controls for every patient were randomly selected from the same cohort. Diarrhea and jaundice were more frequent in patients than in controls (p=0.03). The presence of mucositis, prolonged duration of profound neutropenia and idarubicin treatment proved to be risk factors for typhlitis.