Detection of the floR gene in a diversity of florfenicol resistant Gram-negative bacilli from freshwater salmon farms in Chile

Florfenicol is an important antibiotic in veterinary medicine that is used extensively in aquaculture, including salmon farming in Chile. We analysed a set of 119 florfenicol-resistant Gram-negative bacilli from seven freshwater Chilean salmon farms for the molecular determinants involved in the florfenicol resistance. Ninety-seven of these strains were glucose non-fermenting bacilli, mainly belonging to the Pseudomonas genus, whereas 22 strains were glucose-fermenters. The floR gene was detected in 26 strains (21.8%) that had been isolated from three of the seven salmon farms. Most of the floR-carrying strains were glucose fermenters (21 strains), and most of the floR-carrying strains were also resistant to streptomycin, chloramphenicol and oxytetracycline. The minimum inhibitory concentrations against florfenicol were assessed in the presence and absence of the efflux pump inhibitor Phe-Arg-beta-naphthylamide (MC-207,110). There was evidence that in the majority of non-fermenting bacteria (82 strains), florfenicol resistance was at least partially mediated by non-specific efflux pump systems. Given the diversity of antibiotic resistance patterns observed in this study in the floR-positive isolates, a single antibiotic has the potential to co-select for a diversity of resistances. For this reason, human health as well as animal health can potentially be impacted by the use of antibiotics in aquaculture. To assess this potential risk, future studies should focus on the ability of different antibiotics used in aquatic environments to co-select for multiple resistances, the molecular basis of this diversity of resistance, and whether the genes conferring resistance can be transferred to other bacteria, including those of human health concern.

Drin pesticides removal from aqueous solutions using acid-treated date stones

This work describes the potential applicability of chemically and thermally treated date stones for removing drin pesticides (aldrin, dieldrin and endrin) from aqueous solutions. The effect of several parameters, such as sorbent particle size, adsorbent dose, shaking speed, shaking time, concentration of pesticide solution and temperature, was evaluated by batch experiments. Pesticide determination was carried out using stir bar sorptive extraction and gas chromatography coupled with mass spectroscopy. Maximum removal efficiency (93%) was reached using 0.1 g of acid-treated date stones (ATDS) (63-100 microm) and 100 mL of aldrin (0.5 mg L(-1)). The removal efficiency of drin pesticides decreased in the order of aldrin, dieldrin and endrin, and decreased as the temperature rose. Adsorption data were processed according to various kinetic models. Lagergren and Morris-Weber equations were applied to fit the kinetic results. The second order model was the most suitable on the whole, and intra-particle diffusion was found to be the rate-controlling the adsorption process. According to adsorption kinetic data, 3.5h were considered as the equilibrium time for determining adsorption isotherms. Adsorption data were analyzed by the Langmuir, Freundlich and Dubinin-Radushkevich adsorption approaches. Experimental results showed that the Freundlich isotherm model best described the adsorption process. In addition, thermodynamic parameters such as DeltaH, DeltaS and DeltaG were calculated. Negative values of DeltaH and DeltaG indicate the exothermic and spontaneous nature of pesticide adsorption on ATDS.

The effect of brain hematoma location on volumetric inductive phase shift spectroscopy of the brain with circular and magnetron sensor coils: a numerical simulation study

This numerical simulation study addressed the effects of the location of a discrete brain hematoma on the volumetric inductive phase shift of the brain measured with an induction circular sensor coil and an induction magnetron sensor coil. The theoretical study simulates the brain cavity as a circular sphere transversely centered with respect to the circular and magnetron sensor coils. As a case study for the effects of hematoma location, we employed similar size simulated spherical hematomas placed at three different positions from the center of the brain outward. A three-dimensional finite element analysis of the field equations in the frequency range from 100 kHz to 100 MHz revealed a substantial effect of hematoma location on the ability of both the circular and magnetron sensors to detect the hematomas. In particular it was found that there are frequencies, which may be related to resonance, at which the occurrence of the hematomas has no effect on the volumetric inductive phase shift of the brain. Furthermore it was found that the relative sensitivity of circular and magnetron sensor coils with respect to the occurrence of hematoma varies with the location of the hematoma.

Numerical study of the SNR and SAR of MRI coil arrays

Coil arrays have become a very popular coil configuration for magnetic resonance imaging. This due to that, an image of a larger area can be obtained with uniform sensitivity and higher SNR as compared to standard MR volume coil. Ultra-fast procedures like parallel imaging and phased-array can take advantage of these properties. It is very important to understand the performance of this type of devices to take full advantage of these imaging schemes. Although, the study of the single and coil arrays pose a great challenge because of the mathematical theory involved, a simulation approach can be adopted to study various coil array configuration. The principal objective of this paper is to propose a simple method to study the performance of coil array. This method numerically simulates the electric field, magnetic field, signal-to-noise ratio and specific absorption rate of MRI coil arrays. A strip of squared-shaped coil array is proposed with three different configurations. To numerically compute the electric and magnetic fields, a commercial software tool based on the Finite-Element Method was used to solve the Maxwell's equations. Matrices were formed with the image entries of the electric and magnetic fields, and used to compute the signal-to-noise ratio and specific absorption rate of the coil array configurations. Results showed a good agreement with those reported in the literature. The visualization of the electromagnetic fields allows us to study the behavior of a particular coil array configuration.

Numerical study of the optimal geometry of MRI surface coils

An image based method to compute the signal to noise ratio and specific energy absorption rate of MRI surface resonator coil for different polygonal geometries is proposed. A commercial software tool based on the Finite Element Method was used to numerically solve the Maxwell's equations to form bidimensional images of the electric and magnetic fields. These images represent the point by point fields inside the surface coil. With this data, MATLAB specifically written programs were used to numerically compute the signal to noise ratio and the specific absorption rate for different surface coil geometries. Bidimensional images and contours of the signal to noise ratio and specific absorption rate were also computed and compared. Uniformity profiles of various geometries were calculated using the resulting data to determine the optimal field uniformity. According to the signal to noise ratio images, the squared shaped coil shows the most suitable uniformity for magnetic resonance imaging applications. This can be a good candidate for phased array imaging and parallel imaging.

Evaluation of the leishmanicidal activity of plants used by Peruvian Chayahuita ethnic group

AIM OF THE STUDY

A total of 27 ethanolic plant extracts from 27 species were screened for leishmanicidal activity in vitro against Leishmania amazonensis. Most of the selected species (19) are traditionally used by the Chayahuitas, an Amazonian Peruvian ethnic group, to treat skin affections and/or leishmaniasis.

MATERIAL AND METHODS

A colorimetric method based on the reduction of tetrazolium salt (MTT) was used to measure the viability of Leishmania amazonensis promastigote and amastigote stages.

RESULTS AND CONCLUSIONS

Only the leaves of two species of the Piperaceae family (Piper hispidum Sw., and Piper strigosum Trel.) showed good leishmanicidal activities (IC(50)<10 microg/ml against amastigotes). Roots of Tabernaemontana sananho Ruiz & Pav. (Apocynaceae), together with bark of Vismia tomentosa Ruiz & Pav. (Clusiaceae), fruits of Solanum straminifolium var straminifolium Jacq. (Solanaceae), and stems of Zamia lindenii Regel ex André (Cycadaceae) showed low activity against amastigote stage (IC(50) around 50 microg/ml). Of those only Tabernaemontana sananho displayed also good activity on promastigotes (IC(50)<10 microg/ml). Results are discussed herein, in relation with the traditional use of the plants and compared with other data from the relevant literature.

Imaging of isolated cerebral mucormycosis. A report of three cases

Mucormycosis is a rare infection in immunosupressed patients caused by fungi from the family Mucoraceae. Three types of disease spread have been described: rhinocerebral, systemic and isolated. Isolated spread is the most uncommon form, usually resulting in death. It has been described in diabetics, immunosupressed patients and intravenous drug abusers. Neuroimaging can aid the diagnosis of this entity, but biopsy remains the only reliable method. Imaging findings of Mucormycosis include abscesses and hemorrhagic or ischemic infarcts, usually in the basal ganglia and frontal lobes. Single or multiple lesions have been described as well as meningoencephalitis. Understanding these findings can help to detect the infection in an early stage. We describe three cases of isolated cerebral mucormycosis; all of them were intravenous drug abusers with one patient also being HIV positive.

Glass transition temperature prediction of polymers through the mass-per-flexible-bond principle

A semi-empirical method based on the mass-per-flexible-bond (M/f) principle was used to quantitatively explain the large range of glass transition temperatures (T(g)) observed in a library of 132 L-tyrosine derived homo, co- and terpolymers containing different functional groups. Polymer class specific behavior was observed in T(g) vs. M/f plots, and explained in terms of different densities, steric hindrances and intermolecular interactions of chemically distinct polymers. The method was found to be useful in the prediction of polymer T(g). The predictive accuracy was found to range from 6.4 to 3.7 K, depending on polymer class. This level of accuracy compares favorably with (more complicated) methods used in the literature. The proposed method can also be used for structure prediction of polymers to match a target T(g) value, by keeping the thermal behavior of a terpolymer constant while independently choosing its chemistry. Both applications of the method are likely to have broad applications in polymer and (bio)material science.

Spirolactone iridoids might be responsible for the antileishmanial activity of a Peruvian traditional remedy made with Himatanthus sucuuba (Apocynaceae)

Extracts of seven medicinal plants used specifically against cutaneous leishmaniasis in the Madre de Dios region of Peru were evaluated in vitro against promastigote and axenic amastigote forms of Leishmania amazonensis. One of them showed interesting leishmanicidal activities (IC(50)=5 microg/ml in amastigotes). Bio-guided isolation of the stem bark's ethanol extract of Himatanthus sucuuba (Spruce ex Müll. Arg.) Woodson (Apocynaceae) afforded the spirolactone iridoids isoplumericin and plumericin. The latter showed a reduction of macrophage infection similar to that of the reference drug Amphotericin B (IC(50)=0.9 and 1 microM, respectively). These findings validate the traditional use of Himatanthus sucuuba in the treatment of cutaneous leishmaniasis (Uta) in Peru.

Differences in exhaled breath condensate pH measurements between samples obtained with two commercial devices

BACKGROUND

The objective of this study was to determine differences in EBC pH between samples obtained by RTube and EcoScreen, and to identify the effect of storage at -80 degrees C on the pH values.

METHODS

Twenty-three nonsmoking subjects with asthma or allergic rhinitis or without respiratory disease performed two sequential exhaled breath condensate (EBC) collections, using the RTube collection system and the EcoScreen condenser. EBC pH was measured immediately after collection and after storage at -80 degrees C for 8 weeks, without deaeration and repeated following deaeration with Argon.

RESULTS

In EBC samples without deaeration, the EcoScreen pH values were significantly higher than the RTube pH values (mean difference, 0.32; 95% CI, 0.21-0.44, P < 0.0001). In deaerated EBC samples, the EcoScreen pH values were also significantly higher than the RTube pH values (mean difference, 0.12; 95% CI, 0.01-0.25, P=0.04). For both EBC collection systems, storage for 8 weeks had a significant influence on pH of nondeaerated samples.

CONCLUSIONS

The present study demonstrates that EBC pH value is dependent on the collection device used and that the storage for 8 weeks had a significant influence on the pH of samples analyzed without deaeration.

Finite-Element Electromagnetic Simulation of a Volume Resonator Coil for MR Neuroimaging

The electromagnetic properties of a new volume resonator coil for MR neuroimaging are studied. This coil design is based on a resonator coil called PERES coil. A commercial software tool based on the finite-element method is used to compute the electric and magnetic fields for the quasi- static regime for a specific layout of two coils with 4 rectangular-shaped coils each. Computational experiments were done to calculate the optimal number of nodes and elements in the mesh. This commercial software tool allows us to clearly visualize the electromagnetic properties of the coil as a function of a particular configuration.

Early response to venlafaxine antidepressant correlates with lower ACTH levels prior to pharmacological treatment

A link between stressful life events and development or exacerbation of depression has been established via a large body of evidence. An alteration in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis in depression has also been associated with an increase in cortisol secretion. As arginine-vasopressin (AVP) plays an important role in the activation of HPA axis during stress, the present study investigated ACTH and cortisol secretory response induced by an AVP-related peptide desmopressin (ddAVP) in patients with major depression. Prior to antidepressant treatment, endocrinological parameters were evaluated and correlated with the clinical response to venlafaxine treatment, which offers a dual antidepressant action. Depressive patients with no other psychiatric pathology were evaluated with 17-item Hamilton Depression Scale (HAM-D) in order to follow-up the response to venlafaxine. After 1 wk of treatment, 60% of patients reduced their initial HAM-D score to at least 25%; this group was classified as early responders. The other group (40%) started to reduce significantly their HAM-D score after 3 wk of treatment and was classified as late responders. After 6 wk of treatment both groups have reduced HAM-D score to at least 25% of the baseline score. Prior to the pharmacological treatment, both early and late responders showed salivary cortisol rhythm and urinary free cortisol (UFC) in 24-h similar to healthy subjects. However, we did observe differences in basal ACTH secretion, showing that the late responder group had higher basal ACTH than both early responders and controls. The ddAVP challenge promoted a robust secretion of ACTH only in late responders, suggesting a different sensitivity of pituitary vasopressin receptor. The differences in clinical response to venlafaxine among depressive patients seem to be related to endocrinological parameters.

[Violence scale and severity index: a methodological proposal for measuring violence by the partner in Mexican women]

OBJECTIVE

To construct and validate a scale to assess violence by the male partner against women. An index of severity of the emotional and physical damage was also designed to assess the intensity of the violent actions against women.

MATERIAL AND METHODS

The sample consisted of a total of 26 042 women who participated as respondents in the National Survey on Violence against Women (ENVIM per its abbreviation in Spanish) conducted in Mexico during 2003. Respondents were all users of health services provided by the Mexican government. The questionnaire was organized into 17 sections, one of which was a 27-item scale to assess partner violence. The purpose of this scale was to measure the type (physical, emotional, sexual and financial) and degree of violence based on severity. A severity index was constructed based on two procedures: 1) the validity, reliability, and factor analyses of the scale and 2) the assessment of severity by expert judges who assigned a value to each item of the scale.

RESULTS

The validity and reliability results indicated this scale has adequate internal validity (Cronbach's Alpha = 0.99). The factor analysis with Varimax rotation yielded a four-factor solution. The factors were: 1) Psychological violence; 2) Physical violence; 3) Severe physical violence; and 4) Sexual violence. The combination of the four factors accounted for 62.2% of the variance in the scale. Using the ratings from the judges a table of values for each of the violent actions described was obtained. The scores assigned by the judges ranged from 0 to 354. Results revealed a prevalence of 21% partner violence in the last twelve months. The prevalence of psychological violence was 18.5%; of physical violence 10.1%; severe physical violence 6.7% and sexual violence 7.0%.

CONCLUSION

The scale of violence described in this article is a very useful and reliable instrument to assess marital violence against women. It is suggested that this instrument be used in other settings to compare results with different samples.

[Gender violence prevalence in female users of health services in Mexico]

OBJECTIVE

To identify the prevalence of violence against females among those who are health service beneficiaries in Mexico.

MATERIAL AND METHODS

The National Survey on Violence against Women (ENVIM, per its Spanish abbreviation) was applied in 2003 to female users of public primary and secondary health care services. The sampling framework was based on a stratified, probabilistic sample in two stages. First the health care units were selected with probability proportional to the number of physicians' offices in the unit, from a list of possible care units. Second, women 15 years and older who sought care at the health care unit were selected for participation in the study through systematic sampling. Univariate analysis and then bivariate analysis were carried out on the data collected with a questionnaire.

RESULTS

The sample included 26 042 women between 15 and 92 years of age, with a mean age of 35.8 years. Physical violence during childhood was reported by 42% of the women. Only 7.8% answered yes to a general question about whether they experienced domestic partner violence, but 21.5% reported experiencing violence of any type during the last 12 months as measured by a scale including specific acts of psychological, economic, physical and sexual violence. The most frequently reported type of violence was psychological (19.6%). Of the women who had been pregnant, 14.1% reported having experienced violence during pregnancy, and 4.4% reported being hit in the abdomen. The prevalence of sexual violence was 17.3% and close to half reported being victims of this type of violence before age 15. Higher prevalence of violence was found among women with lower levels of formal education, living in a rented home, in areas with higher overcrowding indices, and users of Ministry of Health care services.

CONCLUSIONS

Identifying and measuring violence is complex, given the diverse types of violence and how they are perceived and therefore reported by women themselves. This is an important public health problem, in view of the high frequency observed in this study and the immediate implications. These findings indicate the urgent need for interventions to prevent and treat violence.

Design and validation of a population-based definition of the metabolic syndrome

OBJECTIVE

The National Cholesterol Education Program (NCEP) definition of the metabolic syndrome was modified to be described as a continuous variable and adapted to the characteristics of a Hispanic population.

RESEARCH DESIGN AND METHODS

Age/sex population percentiles for every component of the NCEP criteria were included in this approach using population-based data from a Mexican nationwide survey (2,158 subjects). One point was given per decile for every component. The total number of points accumulated was used to classify subjects. The predictive power for incident diabetes was evaluated using the 7-year follow-up results of the Mexico City Diabetes Study.

RESULTS

Our population-based method had a significantly better prognostic power compared with the original and the updated NCEP definitions (area under the receiver operating characteristic curve 0.746 vs. 0.697 and 0.723, respectively, P < 0.05). Using individuals with </=1 component of the NCEP definition as reference, the odds ratio was greater in the upper quartile of the points scale (>/=39 points) (12.71 [95% CI 5.67-28.49]) compared with that calculated for the original (9.52 [4.69-19.31]) and the updated (11.14 [5.33-23.30]) NCEP criteria. The major advantage of our approach is the detection of subjects at the extremes of the range of diabetes risk and the ability to estimate this risk as a continuum.

CONCLUSIONS

Our method adapts the NCEP criteria to the characteristics of a Hispanic population. It improves the predictive power of the NCEP criteria for future diabetes.

A role for CD4+CD25+ T cells in regulation of the immune response during human tuberculosis

Active tuberculosis (TB) is associated with prolonged suppression of Mycobacterium tuberculosis (MTB)-specific immune responses, but mechanisms involved are understood incompletely. We investigated a potential role for CD4+CD25+ regulatory T cells in depressed anti-MTB immunity by evaluating serially CD4 cell phenotype and interferon (IFN)-gamma production by mononuclear cells from patients with TB. At diagnosis, frequencies of CD4+CD25+ T cells were increased in blood from TB patients compared to healthy purified protein derivative (PPD)-positive controls (with a history of prior TB exposure), and remained elevated at completion of therapy (6 months). By contrast, expression of another activation marker, CD69, by CD4 T cells was increased at diagnosis, but declined rapidly to control levels with treatment. Among CD4+CD25+ T cells from TB patients at diagnosis those expressing high levels of CD25, probably representing regulatory T cells, were increased 2.9-fold when compared to control subjects, while MTB-stimulated IFN-gamma levels in whole blood supernatants were depressed. A role for CD4+CD25+ T cells in depressed IFN-gamma production during TB was substantiated in depletion experiments, where CD25+-depleted CD4 T cells produced increased amounts of IFN-gamma upon MTB stimulation compared to unseparated T cells. At follow-up, IFN-gamma production improved most significantly in blood from TB patients with high baseline frequencies of CD4+CD25+ T cells (more than threefold higher than controls for both total and CD25hi+ CD4 T cells), who also had a significant drop in frequencies of both total and 'regulatory' CD4+CD25+ T cells in response to treatment. Expansion of CD4+CD25+ regulatory T cells during active TB may play a role in depressed T cell IFN-gamma production.

Localized states in bistable pattern-forming systems

We present a unifying description close to a spatial bifurcation of localized states, appearing as large amplitude peaks nucleating over a pattern of lower amplitude. Localized states are pinned over a lattice spontaneously generated by the system itself. We show that the phenomenon is generic and requires only the coexistence of two spatially periodic states. At the onset of the spatial bifurcation, a forced amplitude equation is derived for the critical modes, which accounts for the appearance of localized peaks.

Intron retention as an alternative splice variant of the rat urocortin 1 gene

Urocortin 1, highly conserved metazoan gene of the corticotropin-releasing hormone family, is a simple gene structured in two exons and the corresponding intron. The urocortin 1 prepropeptide is entirely coded in the second exon. Preliminary non-isotopic in situ hybridization experiments with an oligonucleotide complementary to an intron sequence of the urocortin 1 gene showed a significant cytoplasmic-like staining, suggesting the occurrence of an intron-retained urocortin 1 transcript. This observation prompted us to study whether the urocortin 1 gene presents alternative splicing by intron retention event. Confocal fluorescent in situ hybridization for urocortin 1 RNA and the use of the specific DNA dye TOPRO-3 allowed us to show significant expression of the intron-retained urocortin 1 transcript that did not colocalize with TOPRO-3 staining indicating a cytoplasmic localization for the intron-retained urocortin 1 transcript. The natural occurrence of a polyadenylated intron-retained urocortin 1 RNA was further documented by reverse transcriptase polymerase chain reaction (PCR), primed with oligo(dT), of total RNA extracted from three brain regions, a midbrain region containing the Edinger-Westphal nucleus, cerebellum and prefrontal cortex. In the three brain regions studied, it was possible to amplify both intron-less as well as intron-retained urocortin 1 transcripts. The use of PCR primers that simultaneously amplify both urocortin 1 transcripts allowed us to show that the expression of both urocortin 1 transcripts differs among the brain regions analyzed, suggesting a tissue specific regulation of this alternative splicing. In silico analysis of the five known mammalian urocortin 1 genomic sequences showed high conservation of the urocortin 1 intron sequence. Further studies should investigate the regulation of this intron retention event and its consequence for the functionality of the urocortin 1 gene.

Obesity among children residing in Mexico City and its impact on lung function: a comparison with Mexican-Americans

BACKGROUND

The objective of the study was to describe the prevalence of obesity among Mexican children and its impact on ventilatory lung function.

METHODS

We studied cross-sectionally 6784 students between 8 and 20 years of age attending schools located <2 km away from ten air pollution monitors located throughout metropolitan Mexico City. The comparison group was made up of 1924 Mexican-Americans of the same age, studied during the NHANES-III examination, which included information on spirometry and body mass index (BMI).

RESULTS

Of all our subjects, 9.7% had a BMI >95(th) percentile of CDC growth charts (compared to 15.1% in Mexican-Americans) and 6.6% fulfilled the obesity criteria of the International Obesity Task Force (vs. 12.2%). Obesity was related to male gender, asthma and passive smoking. At the same height and gender, lung function was higher in Mexicans than in Mexican-Americans, perhaps due to altitude. In children 8-11 years of age, lung function increased in heavier subjects but, in older children and youths, function reached a plateau and decreased among children with highest BMI (inverted U pattern, seen in adults).

CONCLUSIONS

Obesity is higher in Mexican-American children and youths than in Mexicans. Spirometric function is affected adversely by obesity, especially in young people.

Epidemiology of type 2 diabetes in Mexico

The epidemiology of diabetes in Mexico is reviewed. In less than four decades, diabetes has become the main health problem in Mexico. It is the principal cause of death in women and the second among men since the year 2000. It is the primary cause of premature retirement, blindness, and kidney failure. By the year 2025, close to 11.7 million Mexicans are expected to be diagnosed with diabetes. In the year 2000, diabetes was the 11th most frequent cause of hospitalization but the second most common cause of hospital mortality. The number of cases reported in children has also increased since 1995. The results of population-based, nationwide surveys have detected a 25% increment over a 7-year period. Fourteen percent of people with diabetes are <40 years of age, and a large proportion of patients have other conditions that determine the appearance of macrovascular complications and kidney failure. In addition, many cases do not reach treatment goals. In conclusion, the growing number of cases and the significant health burden imposed on affected subjects makes diabetes a disease that needs to be prevented. Well-planned strategies are urgently needed to modify the lifestyle of the population and to increase their physical activity. In addition, an enormous effort will be required to educate the population and physicians to improve the diagnosis and treatment of patients with diabetes.