Intranasal sensitization with Blomia Tropicalis antigens induces allergic responses in mice characterized by elevated antigen-specific and non-specific serum ige and peripheral blood eosinophil counts

In order to evaluate the potential allergenicity of Blomia tropicalis (Bt) antigen, IgE production of both specific and non-specific for Bt antigen was monitored in BALB/c mice after exposure to the antigen by nasal route. It was evidenced that B. tropicalis contains a functional allergen in its components. The allergenic components, however, when administered intranasally without any adjuvant, did not function to induce IgE response within a short period. On the other hand, intranasal inoculation of Bt antigens augmented serum IgE responses in mice pretreated by a subcutaneous priming injection of the same antigens. Inoculation of Bt antigen without subcutaneous priming injections induced IgE antibody production only when the antigen was continuously administered for a long period of over 24 weeks. Even when the priming injection was absent, the Bt antigen inoculated with cholera toxin (CT) as a mucosal adjuvant also significantly augmented the Bt antigen-specific IgE responses depending on the dose of CT co-administered. The present study also demonstrated that Bt antigen/CT-inoculated mice showed increased non-specific serum IgE level and peripheral blood eosinophil rates without noticeable elevations of the total leukocyte counts. The immunoblot analysis demonstrated 5 main antigenic components reactive to IgE antibodies induced. These components at about 44-64 kDa position were considered to be an important candidate antigen for diagnosis of the mite-related allergy.

ELEVATED TRANS-MAMMARY TRANSMISSION OF Toxocara canis LARVAE IN BALB/c MICE

Toxocariasis is a widespread zoonosis and is considered an important worldwide public health problem. The aim of this study was to investigate the frequency of trans-mammary Toxocara canis infection in newborn BALB/c mice nursed by females experimentally infected with 1,200 eggs after delivery. After 50 days of age, the presence of larvae in different organs of the offspring was investigated. Trans-mammary infection was confirmed in 73.9% of the mice that had been nursed by infected females. These data show a high trans-mammary transmission of T. canis and confirm the significance of this transmission route in paratenic hosts.

Assessment of the performance of steel fibre reinforced self-compacting concrete in elevated slabs

The reinforcement mechanisms at the cross section level assured by fibres bridging the cracks in steel fibre reinforced self-compacting concrete (SFRSCC) can be significantly amplified at structural level when the SFRSCC is applied in structures with high support redundancy, such is the case of elevated slab systems. To evaluate the potentialities of SFRSCC as the fundamental material of elevated slab systems, a ¼ scale SFRSCC prototype of a residential building was designed, built and tested. The extensive experimental program includes material tests for characterizing the relevant properties of SFRSCC, as well as structural tests for assessing the performance of the prototype at serviceability and ultimate limit conditions. Three distinct approaches where adopted to derive the constitutive laws of the SFRSCC in tension that were used in finite element material nonlinear analysis to evaluate the reliability of these approaches in the prediction of the load carrying capacity of the prototype.

Evaluation of the performance of steel fibre reinforced self-compacting concrete in elevated slab systems; from the material to the structure

Degree of Doctor of Philosophy of Structural/Civil Engineering

Evaluation of the heart rate and arrhythmias following the Maze procedure for chronic atrial fibrillation

PURPOSE: To assess the presence and the prevalence of arrhythmias and the variability of the heart rate in the medium-term postoperative period following the maze procedure for chronic atrial fibrillation (AF). METHODS: Seventeen patients with a mean age of 51.7±12.9 years, who previously underwent the maze procedure without cryoablation for chronic atrial fibrillation, were evaluated with the 24 hour electrocardiogram (ECG) - Holter monitoring from the 6th month after the operation. Valvular and coronary procedures were concomitantly performed. RESULTS: The mean heart rate during Holter monitoring was 82±8bpm; the maximal heart rate was 126 ± 23bpm and the minimal heart rate 57±7bpm. Sinus rhythm was found in 10 (59%) patients and atrial rhythm was found in 7 (41%). Supraventricular extrasystoles had a rate of 2.3±5.5% of the total number of heartbeats and occurred in 16 (94%) patients. Six (35%) patients showed nonsustained atrial tachycardia. Ventricular extrasystoles, with a rate of 0.8±0.5% of the total heartbeats, occurred in 14 (82%) patients. The chronotropic competence was normal in 9 (53%) patients and attenuated in 8 (47%). The atrioventricular conduction (AV) was unchanged in 13 (76%) patients and there were 4 (24%) cases of first degree atrioventricular block (AVB). CONCLUSION: After the maze procedure, the values for the mean heart rate, AV conduction and chronotropic competence approach the normal range, although some cases show attenuation of the chronotropic response, first degree AV block or benign arrhythmias.

Assessment of Thromboembolism After the Cox-Maze Procedure for Chronic Atrial Fibrillation Secondary to Mitral Valve Lesion

OBJECTIVE: To assess the occurrence of late thromboembolism after surgical repair of chronic atrial fibrillation (AF) simultaneously with repair of mitral valve using the Cox-Maze procedure. METHODS: 69 patients underwent Cox 3 procedure, with no cryoablation simultaneously with mitral valvuloplasty or prosthesis. Mean age was 49.9±13.2 years. Mean follow-up was of 31.7±19 months. Types of lesion were as follows: 33 (48%) stenoses, 23 (33%) insufficiencies, and 13 (19%) double lesions. Procedures were: 64 (93%) valvuloplasties, 3 (4%) biological and 2 (3%) mechanical prosthesis placement. There were 9 (13%) patients with previous systemic embolism and 2 (3%) had left atrial thrombi. RESULTS: Early mortality was 7% and late 1%. 2 patients (3%) were reoperated for mitral placement. At last evaluation, 10 patients (15%), were in AF. The remaining 59 (85%) were either in sinus / atrial rythm (74%) or under pacing (12%). There were no occurrence of early or late, systemic or pulmonary embolism. Permanent anticoagulation was employed in 16 cases, 10 in regular rythm and 6 in AF. The remaining 47 (75%), 2 in AF and 45 in regular rythm, did not receive anticoagulants. CONCLUSIONS: These results are in accordance with others series, where the occurrence of embolism was rare after maze procedure. Permanent systemic anticoagulation seems to be unnecessary in those cases.

Elevated Blood Pressure and Obesity in Childhood: A Cross-Sectional Evaluation of 4,609 Schoolchildren

Background: The incidence of obesity in children is increasing worldwide, primarily in urbanized, high-income countries, and hypertension development is a detrimental effect of this phenomenon. Objective: In this cross-sectional study, we evaluated the prevalence of excess weight and its association with high blood pressure (BP) in schoolchildren. Methods: Here 4,609 male and female children, aged 6 to 11 years, from 24 public and private schools in Maringa, Brazil, were evaluated. Nutritional status was assessed by body mass index (BMI) according to cutoff points adjusted for sex and age. Blood pressure (BP) levels above 90th percentile for gender, age and height percentile were considered elevated. Results: The prevalence of excess weight among the schoolchildren was 24.5%; 16.9% were overweight, and 7.6% were obese. Sex and socioeconomic characteristics were not associated with elevated BP. In all age groups, systolic and diastolic BP correlated with BMI and waist and hip measurements, but not with waist-hip ratio. The prevalence of elevated BP was 11.2% in eutrophic children, 20.6% in overweight children [odds ratio (OR), 1.99; 95% confidence interval (CI), 1.61-2.45], and 39.7% in obese children (OR, 5.4; 95% CI, 4.23-6.89). Conclusion: Obese and overweight children had a higher prevalence of elevated BP than normal-weight children. Our data confirm that the growing worldwide epidemic of excess weight and elevated BP in schoolchildren may also be ongoing in Brazil.

Elevated blood pressure prevalence in children did not follow the increase in overweight: results from a school-based study in a rapidly developing country, 1998-2006

Background: Blood pressure (BP) is strongly associated with body weight and there is concern that the pediatric overweight epidemic could lead to an increase in children's mean BP. Objectives: We analyzed BP trends from 1998 to 2006 among children of the Seychelles, a rapidly developing middle-income country in Africa. Methods: Serial school-based surveys of weight, height and BP were conducted yearly between 1998-2006 among all students of the country in four school grades (kindergarten, 4th, 7th and 10th years of compulsory school). We used the CDC criteria to define "overweight" (BMI _95th sex-, and age-specific percentile) and the NHBPEP criteria for "elevated BP" (BP _95th sex-, age-, and height specific percentile). Methods for height, weight, and BP measurements were identical over the study period. The trends in mean BMI and mean systolic/diastolic BP were assessed with linear regression. Results: 27,703 children aged 4-18 years (participation rate: 79%) contributed 43,927 observations on weight, height, and BP. The prevalence of overweight increased from 5.1% in 1998-2000 to 8.1% in 2004-2006 among boys, and from 6.1% to 9.1% among girls, respectively. The prevalence of elevated BP was 8.4% in 1998-2000 and 6.9% in 2004-2006 among boys; 9.8% and 7.8% among girls, respectively. Over the 9-years study period, age-adjusted body mass index (BMI) increased by 0.078 kg/m2/year in boys and by 0.083 kg/m2/year in girls (both sexes, P_0.001). Age- and height-adjusted systolic BP decreased by -0.37 mmHg/year in boys and by -0.34 mmHg/year in girls (both sexes, P_0.001). Diastolic BP did not change in boys (-0.02 mmHg/year, P: 0.40) and slightly increased in girls (0.07 mmHg/year, P: 0.003). These trend estimates were altered modestly upon further adjustment for BMI or if analyses were based on median rather than mean values. Conclusion: Although body weight increased markedly between 1998 and 2006 in this population, systolic BP decreased and diastolic BP changed only marginally. This suggests that population increases in body weight are not necessarily associated with corresponding rises in BP in children.

Accurate performance of a rat model of schizophrenia in the water maze depends on visual cue availability and stability: a distortion in cognitive mapping abilities?

Rats were treated postnatally (PND 5-16) with BSO (l-buthionine-(S,R)-sulfoximine) in an animal model of schizophrenia based on transient glutathione deficit. The BSO treated rats were impaired in patrolling a maze or a homing table when adult, yet demonstrated preserved escape learning, place discrimination and reversal in a water maze task [37]. In the present work, BSO rats' performance in the water maze was assessed in conditions controlling for the available visual cues. First, in a completely curtained environment with two salient controlled cues, BSO rats showed little accuracy compared to control rats. Secondly, pre-trained BSO rats were impaired in reaching the familiar spatial position when curtains partially occluded different portions of the room environment in successive sessions. The apparently preserved place learning in a classical water maze task thus appears to require the stability and the richness of visual landmarks from the surrounding environment. In other words, the accuracy of BSO rats in place and reversal learning is impaired in a minimal cue condition or when the visual panorama changes between trials. However, if the panorama remains rich and stable between trials, BSO rats are equally efficient in reaching a familiar position or in learning a new one. This suggests that the BSO accurate performance in the water maze does not satisfy all the criteria for a cognitive map based navigation on the integration of polymodal cues. It supports the general hypothesis of a binding deficit in BSO rats.

Coloration signals the ability to cope with elevated stress hormones: effects of corticosterone on growth of barn owls are associated with melanism.

Stressful situations during development can shape the phenotype for life by provoking a trade-off between development and survival. Stress hormones, mainly glucocorticoids, play an important orchestrating role in this trade-off. Hence, how stress sensitive an animal is critically determines the phenotype and ultimately fitness. In several species, darker eumelanic individuals are less sensitive to stressful conditions than less eumelanic conspecifics, which may be due to the pleiotropic effects of genes affecting both coloration and physiological traits. We experimentally tested whether the degree of melanin-based coloration is associated with the sensitivity to an endocrine response to stressful situations in the barn owl. We artificially administered the mediator of a hormonal stress response, corticosterone, to nestlings to examine the prediction that corticosterone-induced reduction in growth rate is more pronounced in light eumelanic nestlings than in darker nest mates. To examine whether such an effect may be genetically determined, we swapped hatchlings between randomly chosen pairs of nests. We first showed that corticosterone affects growth and, thus, shapes the phenotype. Second, we found that under corticosterone administration, nestlings with large black spots grew better than nestlings with small black spots. As in the barn owl the expression of eumelanin-based coloration is heritable and not sensitive to environmental conditions, it is therefore a reliable, genetically based sign of the ability to cope with an increase in blood corticosterone level.

Separate neuronal and glial Na+,K+-ATPase isoforms regulate glucose utilization in response to membrane depolarization and elevated extracellular potassium.

The role of cell type-specific Na+,K+-ATPase isozymes in function-related glucose metabolism was studied using differentiated rat brain cell aggregate cultures. In mixed neuron-glia cultures, glucose utilization, determined by measuring the rate of radiolabeled 2-deoxyglucose accumulation, was markedly stimulated by the voltage-dependent sodium channel agonist veratridine (0.75 micromol/L), as well as by glutamate (100 micromol/L) and the ionotropic glutamate receptor agonist N-methyl-D-aspartate (NMDA) (10 micromol/L). Significant stimulation also was elicited by elevated extracellular potassium (12 mmol/L KCl), which was even more pronounced at 30 mmol/L KCl. In neuron-enriched cultures, a similar stimulation of glucose utilization was obtained with veratridine, specific ionotropic glutamate receptor agonists, and 30 mmol/L but not 12 mmol/L KCl. The effects of veratridine, glutamate, and NMDA were blocked by specific antagonists (tetrodotoxin, CNQX, or MK801, respectively). Low concentrations of ouabain (10(-6) mol/L) prevented stimulation by the depolarizing agents but reduced only partially the response to 12 mmol/L KCl. Together with previous data showing cell type-specific expression of Na+,K+-ATPase subunit isoforms in these cultures, the current results support the view that distinct isoforms of Na+,K+-ATPase regulate glucose utilization in neurons in response to membrane depolarization, and in glial cells in response to elevated extracellular potassium.

Elevated resource availability sufficient to turn opportunistic into virulent fish pathogens.

There is mounting evidence that organic or inorganic enrichment of aquatic environments increases the risk of infectious diseases, with disease agents ranging from helminth parasites to fungal, bacterial, and viral pathogens. The causal link between microbial resource availability and disease risk is thought to be complex and, in the case of so-called "opportunistic pathogens," to involve additional stressors that weaken host resistance (e.g., temperature shifts or oxygen deficiencies). In contrast to this perception, our experiment shows that the link between resource levels and infection of fish embryos can be very direct: increased resource availability can transform benign microbial communities into virulent ones. We find that embryos can be harmed before further stresses (e.g., oxygen depletion) weaken them, and treatment with antibiotics and fungicides cancels the detrimental effects. The changed characteristics of symbiotic microbial communities could simply reflect density-dependent relationships or be due to a transition in life-history strategy. Our findings demonstrate that simple microhabitat changes can be sufficient to turn "opportunistic" into virulent pathogens.