Human case of gastric infection by a fourth larval stage of Pseudoterranova decipiens (Nematoda, Anisakidae)

Only three cases of human infection by anisakid nematodes have been reported in Chile since 1976. In the present case, an anisakid worm, identified as a fourth-stage Pseudoterranova decipiens larva, was removed with a gastroendoscopic biopsy clipper from the stomach of a 45 year-old man from southern Chile. The patient, who presented acute epigastric pain and a continuous sensation of having an empty stomach, reported having eaten smoked fish. The worm was fixed in 70% ethanol and cleaned in lactophenol for morphological study. The morphometric characteristics of the worm are described and drawn. Anisakid larvae in fish flesh can be killed by freezing or cooking.

HIV/tuberculosis co-infection: a request for a better surveillance

The increasing endemicity of tuberculosis resulting from causes such as immigration, poverty, a declining public health infrastructure and co-infection by HIV/Mycobacterium tuberculosis, is leading to a change in tuberculosis control programmes. One of the main reasons for the resurgence of tuberculosis is HIV infection - the risk of tuberculosis is greater in HIV patients than in the majority of the population as can be seen from numerous research projects. The need for systematic testing for HIV infection in all tuberculosis patients by undertaking confidential HIV tests on admission to a tuberculosis programme is brought out. This measure would increase the number of cases diagnosed and provide data for better surveillance of the co-infection.

Susceptibility of asthmatic children to respiratory infection

OBJECTIVE: A case-control study of patients with pneumonia was conducted to investigate whether wheezing diseases could be a risk factor. METHODS: A random sample was taken from a general university hospital in S. Paulo City between March and August 1994 comprising 51 cases of pneumonia paired by age and sex to 51 non-respiratory controls and 51 healthy controls. Data collection was carried out by two senior paediatricians. Diagnoses of pneumonia and presence of wheezing disease were independently established by each paediatrician for both cases and controls. Pneumonia was radiologically confirmed and repeatability of information on wheezing diseases was measured. Logistic regression analysis was used to identify risk factors. RESULTS: Wheezing diseases, interpreted as proxies of asthma, were found to be an important risk factor for pneumonia with an odds ratio of 7.07 (95%CI= 2.34-21.36), when the effects of bedroom crowding (odds ratio = 1.49 per person, 95%CI= 0.95-2.32) and of low family income (odds ratio = 5.59 against high family income, 95%CI= 1.38-22.63) were controlled. The risk of pneumonia attributable to wheezing diseases is tentatively calculated at 51.42%. CONCLUSION: It is concluded that at practice level asthmatics should deserve proper surveillance for infection and that at public health level pneumonia incidence could be reduced if current World Health Organisation's guidelines were reviewed as to include comprehensive care for this illness.

Chaos and crises in a model for cooperative hunting: A symbolic dynamics approach

In this work we investigate the population dynamics of cooperative hunting extending the McCann and Yodzis model for a three-species food chain system with a predator, a prey, and a resource species. The new model considers that a given fraction sigma of predators cooperates in prey's hunting, while the rest of the population 1-sigma hunts without cooperation. We use the theory of symbolic dynamics to study the topological entropy and the parameter space ordering of the kneading sequences associated with one-dimensional maps that reproduce significant aspects of the dynamics of the species under several degrees of cooperative hunting. Our model also allows us to investigate the so-called deterministic extinction via chaotic crisis and transient chaos in the framework of cooperative hunting. The symbolic sequences allow us to identify a critical boundary in the parameter spaces (K, C-0) and (K, sigma) which separates two scenarios: (i) all-species coexistence and (ii) predator's extinction via chaotic crisis. We show that the crisis value of the carrying capacity K-c decreases at increasing sigma, indicating that predator's populations with high degree of cooperative hunting are more sensitive to the chaotic crises. We also show that the control method of Dhamala and Lai [Phys. Rev. E 59, 1646 (1999)] can sustain the chaotic behavior after the crisis for systems with cooperative hunting. We finally analyze and quantify the inner structure of the target regions obtained with this control method for wider parameter values beyond the crisis, showing a power law dependence of the extinction transients on such critical parameters.

Pricing intraday dynamics across EUAS and CERS markets

The relative contribution of European Union Allowances (EUAs) and Certified Emission Reductions (CERs) to the price discovery of their common true value has been empirically studied using daily data with inconclusive results. In this paper, we study the short-run and long-run price dynamics between EUAs and CERs future contracts using intraday data. We report a bidirectional feedback causality relationship both in the short-run and in the long-run, with the EUA's market being the leader.

Cytomegalovirus seroepidemiology in an urban community of São Paulo, Brazil

INTRODUCTION: After the era of rubella vaccine, cytomegalovirus (CMV) infection is one of the most frequently causes of mental retardation and congenital deafness. Seroepidemiological studies are necessary to understand the transmission dynamics of the disease. The purpose of the study was to quantify the transmission rate of CMV disease in a community in the state of São Paulo, Brazil. METHODS: Using ELISA test (IgG), a retrospective serological survey looking for CMV antibodies was performed in an non-immunized community. Frozen sera from 443 individuals, randomly selected by cluster sampling technique in the town of Caieiras, São Paulo, were collected from November 1990 to January 1991. Seroprevalence was stratified by age (0-40 years). Mathematical techniques were applied to determine the age-dependent decay function of maternal antibodies during the first year of life, the age-dependent seroprevalence function and the force of infection for CMV in this community. RESULTS: It was observed a descending phase of seropositivity in the first 9 months, but changes in antibody titration were observed between 8 months old and one year of age. The average age of the first infection was 5.02 months of age and 19.84 years, when the age-dependent seroprevalence and the force of infection were analyzed between 10 months of age and 10 years of age and from 10 to 40 years old, respectively. CONCLUSION: CMV infection is highly prevalent among the population studied and infection occurs in the first year of life. This study shows that most women at reproductive age are vulnerable to the first infection, increasing the risk for congenital infection.

Entropy analysis of DNA code dynamics in human chromosomes

Deoxyribonucleic acid, or DNA, is the most fundamental aspect of life but present day scientific knowledge has merely scratched the surface of the problem posed by its decoding. While experimental methods provide insightful clues, the adoption of analysis tools supported by the formalism of mathematics will lead to a systematic and solid build-up of knowledge. This paper studies human DNA from the perspective of system dynamics. By associating entropy and the Fourier transform, several global properties of the code are revealed. The fractional order characteristics emerge as a natural consequence of the information content. These properties constitute a small piece of scientific knowledge that will support further efforts towards the final aim of establishing a comprehensive theory of the phenomena involved in life.

Fractional dynamics in DNA

This paper addresses the DNA code analysis in the perspective of dynamics and fractional calculus. Several mathematical tools are selected to establish a quantitative method without distorting the alphabet represented by the sequence of DNA bases. The association of Gray code, Fourier transform and fractional calculus leads to a categorical representation of species and chromosomes.

Possible respiratory infection due to Aspergillus in workers from swineries and poultries

Recent epidemiologic studies clearly outline the link between fungal sensibilization and exarcebations of asthma, leading to increased morbidity and mortality. Amongst the filamentous fungi, Aspergillus scpecies have been strongly linked with exarcebations of asthma and other respiratory allergic diseases. Particles of approximately 1 to 4 pm are deposited in the lower respiratory tract. Therefore, conidia of A. fumigatus are small enough to traverse the terminal respiratory airways and reach the pulmonary alveoli, whereas the larger conidia of some other Aspergillus species, such as A. flavus and A. niger, tend to be deposited in the paranasal sinuses and upper airways. Exposute to environmental fungal spores has been associated with worsening asthma symptoms, lung function, hospital admissions and asthma-related deaths.

Autoinhibition of TBCB regulates EB1-mediated microtubule dynamics

Tubulin cofactors (TBCs) participate in the folding, dimerization, and dissociation pathways of the tubulin dimer. Among them, TBCB and TBCE are two CAP-Gly domain-containing proteins that together efficiently interact with and dissociate the tubulin dimer. In the study reported here we showed that TBCB localizes at spindle and midzone microtubules during mitosis. Furthermore, the motif DEI/M-COO− present in TBCB, which is similar to the EEY/F-COO− element characteristic of EB proteins, CLIP-170, and α-tubulin, is required for TBCE–TBCB heterodimer formation and thus for tubulin dimer dissociation. This motif is responsible for TBCB autoinhibition, and our analysis suggests that TBCB is a monomer in solution. Mutants of TBCB lacking this motif are derepressed and induce microtubule depolymerization through an interaction with EB1 associated with microtubule tips. TBCB is also able to bind to the chaperonin complex CCT containing α-tubulin, suggesting that it could escort tubulin to facilitate its folding and dimerization, recycling or degradation.

Prevalence of Helicobacter pylori infection in Fortaleza, Northeastern Brazil

The prevalence of Helicobacter pylori infection was assessed in a randomly selected sample of individuals from low-income community in Fortaleza, Northeastern Brazil. Overall, 384 out of 610 participants (62.9%) were H. pylori positive. A 47.5% infection rate was found in subjects aged six months to 10 years old, increased to 73.3% in subjects aged 11-20 years and then continued to increase with age reaching up to 87% in those over 60 years old. After this age group, the prevalence decreased slightly. The prevalence of infection increased significantly with age (p<0.0001).

HIV infection and AIDS in a small municipality in Southeast Brazil

OBJECTIVE: Studies on the aspects of HIV infection in small Brazilian municipalities are invaluable to appropriately design control strategies, better allocate resources, and improve health care services. The objective of the study was to assess the clinical and epidemiological aspects of HIV infection in a small municipality. METHODS: A descriptive study was carried out in Miracema, a small municipality in the northwestern area of the state of Rio de Janeiro, Brazil, between July 1999 and December 2003. All HIV-infected adult patients followed up at the local HIV/AIDS Program were included. Clinical and epidemiologic characteristics were prospectively assessed through standardized questionnaires. RESULTS: A total of 65 adult patients who attended the local HIV/AIDS Program were analyzed. Most (34) were women (male to female ratio: 0.9). An absolute predominance of patients who were born in Miracema or neighboring municipalities (94%), lived in Miracema (90.7%), were single (70.8%), attributed the acquisition of HIV infection to unprotected heterosexual intercourse (72.3%) and had a past history of snorting cocaine (27.7) was found Central nervous system disorders (including five cases of cryptococcal meningitis) and acute pulmonary pneumocystosis-like respiratory failure were major causes of morbidity. Most patients (56.9%) were at presented in advanced stages of HIV infection. CONCLUSIONS: The predominance of patients on advanced stages of HIV infection suggest the existence of a large pool of undiagnosed cases in the community. A major feature of the cohort was an inverted male to female ratio. Further investigations over a broader geographic area are urgently needed for better understanding the clinical and epidemiological characteristics of HIV infection in small Brazilian municipalities and rural areas.

Symbolic dynamics and renormalization of non-autonomous k periodic dynamical systems

The purpose of this paper was to introduce the symbolic formalism based on kneading theory, which allows us to study the renormalization of non-autonomous periodic dynamical systems.

An Extension of Gompertzian Growth Dynamics Weibull and Frechet Models

In this work a new probabilistic and dynamical approach to an extension of the Gompertz law is proposed. A generalized family of probability density functions, designated by Beta* (p, q), which is proportional to the right hand side of the Tsoularis-Wallace model, is studied. In particular, for p = 2, the investigation is extended to the extreme value models of Weibull and Frechet type. These models, described by differential equations, are proportional to the hyper-Gompertz growth model. It is proved that the Beta* (2, q) densities are a power of betas mixture, and that its dynamics are determined by a non-linear coupling of probabilities. The dynamical analysis is performed using techniques of symbolic dynamics and the system complexity is measured using topological entropy. Generally, the natural history of a malignant tumour is reflected through bifurcation diagrams, in which are identified regions of regression, stability, bifurcation, chaos and terminus.

Topological Complexity and Predictability in the Dynamics of a Tumor Growth Model with Shilnikov's Chaos

Dynamical systems modeling tumor growth have been investigated to determine the dynamics between tumor and healthy cells. Recent theoretical investigations indicate that these interactions may lead to different dynamical outcomes, in particular to homoclinic chaos. In the present study, we analyze both topological and dynamical properties of a recently characterized chaotic attractor governing the dynamics of tumor cells interacting with healthy tissue cells and effector cells of the immune system. By using the theory of symbolic dynamics, we first characterize the topological entropy and the parameter space ordering of kneading sequences from one-dimensional iterated maps identified in the dynamics, focusing on the effects of inactivation interactions between both effector and tumor cells. The previous analyses are complemented with the computation of the spectrum of Lyapunov exponents, the fractal dimension and the predictability of the chaotic attractors. Our results show that the inactivation rate of effector cells by the tumor cells has an important effect on the dynamics of the system. The increase of effector cells inactivation involves an inverse Feigenbaum (i.e. period-halving bifurcation) scenario, which results in the stabilization of the dynamics and in an increase of dynamics predictability. Our analyses also reveal that, at low inactivation rates of effector cells, tumor cells undergo strong, chaotic fluctuations, with the dynamics being highly unpredictable. Our findings are discussed in the context of tumor cells potential viability.