Collagen extraction from mussel byssus: a new marine collagen source with physicochemical properties of industrial interest.

Mussel byssus is a by-product of mussel production and is a potential source of collagen. The goal of this study was to extract collagen from the byssus of Chilean mussel using an enzymatic method and characterize it. A pepsin-aided extraction method was employed where first an enzymatic hydrolysis at two pepsin/substrate ratios (1:50 or 4:50) and times (4 or 24 h) was done. Extraction was conducted at 80 °C for 24 h, in a 0.5 N acetic acid solution. All samples were analyzed for collagen content, amino acid profile, turbidity, viscosity, solubility, denaturation temperature and surface tension. Hydrolysis time had significant effect on collagen content, hydroxyproline content and extraction yield. Hydrolysis with a pepsin/byssus ratio of 4:50 for 24 h gave the better extraction performance with values of 69 mg/g protein, 1.8 mg/g protein and 30%, for collagen content, hydroxyproline content and extraction yield, respectively. No differences were found for the viscosity and surface tension of collagen dispersions, suggesting that the enzymatic hydrolysis did not affect the integrity of the collagen molecule. Denaturation temperature of freeze-dried byssus collagen presented a high value (83-91 °C), making this kind of collagen a very interesting material for encapsulation of bioactive molecules and for biomedical applications.

[Implications of chilean legal framework in teen pregnancy prevention: conflict and insecurity in health professionals]. / Implicancias del marco legal chileno en la prevención del embarazo adolescente: conflicto e inseguridad en los profesionales de la salud.

BACKGROUND: Teenage pregnancy is a psychosocial and multifactorial problem described as a lack of exercise of rights in sexual and reproductive health. There are important aspects in the doctor-patient relationship and confidentiality that directly affect the continuity and quality of care. There are controversies in the laws relating to the provision of contraception and confidentiality, and those that protect the sexual indemnity, especially in adolescents under 14 years. AIM: To describe the implications of the legal framework for professional midwives in the care of adolescents younger than 14 years in sexual and reproductive health. MATERIAL AND METHODS: In-depth interviews were conducted to 13 female and 2 male midwives working at Primary Health Care Centers in the Metropolitan Region. RESULTS: The attention of adolescents younger than 14 years in sexual and reproductive health involves medical-legal issues for health professionals. All professionals recognize that mandatory reporting sexual activity is a complex situation. All professionals notify pregnancies. In relation to the delivery of contraception, clinical care is problematic since professionals should take shelter from a legal standpoint. CONCLUSIONS: The medical-legal context of pregnant women under 14 years of age care generates a context of uncertainty and fear for professionals and becomes a source of conflict and insecurity in the exercise of the profession.

Effect of soil slope on the appearance of Mycobacterium avium subsp. paratuberculosis in water running off grassland soil after application of contaminated slurry.

The study assessed the effect of soil slope on Mycobacterium avium subsp. paratuberculosis transport into rainwater runoff from agricultural soil after application of M. avium subsp. paratuberculosis-contaminated slurry. Under field conditions, 24 plots of undisturbed loamy soil 1 by 2 m(2) were placed on platforms. Twelve plots were used for water runoff: 6 plots at a 3% slope and 6 plots at a 15% slope. Half of the plots of each slope were treated with M. avium subsp. paratuberculosis-contaminated slurry, and half were not treated. Using the same experimental design, 12 plots were established for soil sampling on a monthly basis using the same spiked slurry application and soil slopes. Runoff following natural rainfall was collected and analyzed for M. avium subsp. paratuberculosis, coliforms, and turbidity. M. avium subsp. paratuberculosis was detected in runoff from all plots treated with contaminated slurry and one control plot. A higher slope (15%) increased the likelihood of M. avium subsp. paratuberculosis detection but did not affect the likelihood of finding coliforms. Daily rainfall increased the likelihood that runoff would have coliforms and the coliform concentration, but it decreased the M. avium subsp. paratuberculosis concentration in the runoff. When there was no runoff, rain was associated with increased M. avium subsp. paratuberculosis concentrations. Coliform counts in runoff were related to runoff turbidity. M. avium subsp. paratuberculosis presence/absence, however, was related to turbidity. Study duration decreased bacterial detection and concentration. These findings demonstrate the high likelihood that M. avium subsp. paratuberculosis in slurry spread on pastures will contaminate water runoff, particularly during seasons with high rainfall. M. avium subsp. paratuberculosis contamination of water has potential consequences for both animal and human health.

Influence of the particle size and hydrocolloid type on lipid digestion of thickened emulsions.

Hydrocolloids are used as stabilizing agents in order to enhance the physical stability of emulsions during their storage. However, they can also play an important role in nutrient release and bioavailability. In this context, the aim of this research was to study the effect of the emulsion type and thickener type on the physical-structural changes and free fatty acid release during in vitro digestion. Oil-in-water emulsions were prepared with different particle sizes (CE: conventional emulsions and NE: nanoemulsions) and thickening agents (starch and xanthan gum). The experimental conditions of homogenization used allowed food emulsions to be obtained at the microscale and nanoscale, with particle sizes ranging among 3.2-3.4 µm and 78-107 nm for CE and NE, respectively. The addition of thickening agents (XG and ST) modified the physical properties of emulsions (particle size, zeta potential and stability) slightly, and thickened samples with similar viscosity were obtained. The kinetics of FFAs released during the in vitro intestinal digestion showed no significant differences (p > 0.05) in the digestion rate among samples; however, emulsion and thickener types decreased the final extent of free fatty acids, being more evident for those samples with starch. Xanthan gum kept the particle size of nanoemulsions stable during the oral and gastric phases, which promoted the release of FFAs during the intestinal phase. Therefore, xanthan gum could be used as a thickening agent of nanoemulsions exerting a minor impact on their lipid bioaccessibility.

[Adolescent drug use. Ethical dilemma in the diagnostic-therapeutic approach]. / Consumo de drogas en adolescentes. Dilema ético en el abordaje diagnóstico-terapéutico.

Illegal drug use among adolescents has increased in recent years in Spain, as well as has the risk behaviours and problems typical of adolescence. The results of studies on drug use during this stage of life reveal the serious and wide-ranging consequences that can arise. Emergency services are often the first to receive and deal with these and its professionals must face situations that pose contradictions between two of the basic ethical principles, the principle of autonomy and the principle of beneficence; an ethical dilemma that is addressed in this work.

Progressive neuronal and motor dysfunction in mice overexpressing the serine protease inhibitor protease nexin-1 in postmitotic neurons.

Perturbation of the homeostasis between proteases and their inhibitors has been associated with lesion-induced or degenerative neuronal changes. Protease nexin-1 (PN-1), a secreted serine protease inhibitor, is constitutively expressed in distinct neuronal cell populations of the adult CNS. In an earlier study we showed that transgenic mice with ectopic or increased expression of PN-1 in postnatal neurons have altered synaptic transmission. Here these mice are used to examine the impact of an extracellular proteolytic imbalance on long-term neuronal function. These mice develop disturbances in motor behavior from 12 weeks on, with some of the histopathological changes described in early stages of human motor neuron disease, and neurogenic muscle atrophy in old age. In addition, sensorimotor integration, measured by epicranial multichannel recording of sensory evoked potentials, is impaired. Our results suggest that axonal dysfunction rather than cell death underlies these phenotypes. In particular, long projecting neurons, namely cortical layer V pyramidal and spinal motor neurons, show an age-dependent vulnerability to PN-1 overexpression. These mice can serve to study early stages of in vivo neuronal dysfunction not yet associated with cell loss.

Application of cattle slurry containing Mycobacterium avium subsp. paratuberculosis (MAP) to grassland soil and its effect on the relationship between MAP and free-living amoeba.

Slurry from dairy farms is commonly used to fertilize crops and pastures. This mixture of manure, urine and water can harbor multiple microbial pathogens among which Mycobacterium avium subsp. paratuberculosis (MAP) is a major concern. Persistence of MAP in soil and infection of soil Acanthamoeba was evaluated by culture, real-time IS900 PCR, and by staining of amoeba with acid-fast and vital stains comparing soils irrigated with MAP-spiked or control dairy farm slurry. MAP DNA was detected in soil for the 8 month study duration. MAP was detected by PCR from more soil samples for plots receiving MAP-spiked slurry (n=61/66) than from soils receiving control slurry (n=10/66 samples). Vital stains verified that intracellular MAP in amoeba was viable. More MAP was found in amoeba at the end of the study than immediately after slurry application. There was no relationship between MAP presence in soil and in amoeba over time. Infection of amoeba by MAP provides a protected niche for the persistence and even possibly the replication of MAP in soils. As others have suggested, MAP-infected amoeba may act like a "Trojan horse" providing a means for persistence in soils and potentially a source of infection for grazing animals.

Epicranial sensory evoked potential recordings for repeated assessment of cortical functions in mice.

In the present study, we describe a simple and minimally invasive method to record sensory evoked potentials (SEP) in the anesthetized mouse. The hardware includes a 16-channel acquisition system with a high signal/noise ratio and high temporal resolution. Under general anesthesia the skull is exposed and stainless steel electrodes are placed directly over the bone. A computer controlled electromechanical stimulation is applied to a single whisker or a group of whiskers unilaterally and cortical responses are recorded bilaterally. Primary SEP are detected over the contralateral barrel cortex, but delayed signals appear over the motor cortex, secondary somatosensory cortex and the ipsilateral hemisphere. The size of evoked SEP correlates with the number of stimulated whiskers and responses are reproducible and consistent over time when recorded repeatedly for up to 6 weeks. We conclude that epicranial multichannel recording of SEP represents an interesting, minimally invasive approach to monitor repeatedly cortical activity and study certain aspects of long-term plasticity of evoked responses in mice.

Light-induced arousal affects simultaneously EEG and heart rate variability in the rat.

In awaken rats, ECG and EEG were simultaneously analysed in order to quantify the cortical EEG and beat-to-beat heart rate variability (HRV) in response to light onset. The HRV bands LF (40-200 mHz), MF (200-600 mHz) and HF (600-2500 mHz) and the EEG bands delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz) and beta (13-32 Hz) were assessed. Light onset induced a significant arousal reaction in the EEG, manifested by a global decrease in total spectral power and a shift towards theta and beta bands, while total HRV spectral power increased, with a shift to the sympathetic-related MF band. This simultaneous changes in HRV and EEG induced by light onset could be triggered by the same common factor that controls both oscillatory responses.

Evaluation of PMS-PCR technology for detection of Mycobacterium avium subsp. paratuberculosis directly from bovine fecal specimens.

Mycobacterium avium subsp. paratuberculosis (MAP) causes paratuberculosis, or Johne's disease, in animals. Diagnosis of MAP infection is challenging because of the pathogen's fastidious in vitro growth requirements and low-level intermittent shedding in feces during the preclinical phase of the infection. Detection of these "low-shedders" is important for effective control of paratuberculosis as these animals serve as sources of infection for susceptible calves. Magnetic separation technology, used in combination with culture or molecular methods for the isolation and detection of pathogenic bacteria, enhances the analytical sensitivity and specificity of detection methods. The aim of the present study was to evaluate peptide-mediated magnetic separation (PMS) capture technology coupled with IS900 PCR using the Roche real-time PCR system (PMS-PCR), in comparison with fecal culture using BACTEC-MGIT 960 system, for detection of MAP in bovine fecal samples. Among the 351 fecal samples 74.9% (263/351) were PMS-PCR positive while only 12.3% (43/351) were MGIT culture-positive (p=0.0001). All 43 MGIT culture-positive samples were also positive by PMS-PCR. Mean PMS-PCR crossing-point (Cp) values for the 13 fecal samples with the highest number of MAP, based on time to detection, (26.3) were significantly lower than for the 17 fecal samples with <100 MAP per 2g feces (30.06) (p<0.05). PMS-PCR technology provided results in a shorter time and yielded a higher number of positive results than MGIT culture. Earlier and faster detection of animals shedding MAP by PMS-PCR should significantly strengthen control efforts for MAP-infected cattle herds by helping to limit infection transmission at earlier stages of the infection.

[Profile of adolescents seen in emergency departments with acute alcohol poisoning]. / Perfil de los adolescentes que acuden a urgencias por intoxicación enólica aguda.

INTRODUCTION: In recent years, the prevalence of Acute Alcohol Intoxication (AAI) in adolescents has increased. One of its impacts had been the increase in consultations in the Emergency Services (ES). The objective of this study is to assess the psychosocial profile of adolescents who consult for AAI and study their personal, family and social functioning. METHODS: 104 families of adolescents who attended for AAI in ES and 104 controls, matched by age and sex, were interviewed by telephone to obtain sociodemographic, clinical, academic and family functioning data. RESULTS: 72% of the adolescents who were attended for AAI were under 16 years old. Academic data showed that 37.7% had repeated a school year, 20% had truancy and 19.6% abandoned their basic studies. 9,8% were in psychiatric treatment. Only 11.4% of patients were referred to specialist service. There were no significant differences between in any of the clinical variables between the study and control group. CONCLUSIONS: This study provides new information on the characteristics of this population and provides guidance on the need to develop protocols for working in the ES that includes not only biochemical/ toxicological parameters but also includes the assessment of psychosocial parameters.

Implicancias del marco legal chileno en la prevención del embarazo adolescente: conflicto e inseguridad en los profesionales de la salud / Implications of chilean legal framework in teen pregnancy prevention: conflict and insecurity in health professionals

Background: Teenage pregnancy is a psychosocial and multifactorial problem described as a lack of exercise of rights in sexual and reproductive health. There are important aspects in the doctor-patient relationship and confidentiality that directly affect the continuity and quality of care. There are controversies in the laws relating to the provision of contraception and confidentiality, and those that protect the sexual indemnity, especially in adolescents under 14 years. Aim: To describe the implications of the legal framework for professional midwives in the care of adolescents younger than 14 years in sexual and reproductive health. Material and Methods: In-depth interviews were conducted to 13 female and 2 male midwives working at Primary Health Care Centers in the Metropolitan Region. Results: The attention of adolescents younger than 14 years in sexual and reproductive health involves medical-legal issues for health professionals. All professionals recognize that mandatory reporting sexual activity is a complex situation. All professionals notify pregnancies. In relation to the delivery of contraception, clinical care is problematic since professionals should take shelter from a legal standpoint. Conclusions: The medical-legal context of pregnant women under 14 years of age care generates a context of uncertainty and fear for professionals and becomes a source of conflict and insecurity in the exercise of the profession.

Detection of mycobacterium avium subsp. paratuberculosis in a cattle/pudu interface / Detecção de mycobacterium avium subsp. paratuberculosis em uma interface gado/pudu

Mycobacterium avium subsp. paratuberculosis (Map) is the etiological agent of paratuberculosis. In Chile, information about Map isolation from both domestic ruminant and wildlife species has been accumulating, but it has to be extended to other species. The present study focuses specifically on one wild grazing species, the pudu (Pudu puda), one of the less known South American deer considered an endangered species that shares pastures with cattle in southern Chile, where the greatest part of the country's dairy cattle population is located. Convenient samples from 3 pudus were collected from one dairy farm where Map infection had previously been confirmed in cattle. All three pudus shed the bacterium in feces and the isolates are the same type of Map as described for cattle. This study represents the first case report of Map isolation in the pudu captured from the wild. It is also the first documented association between a Map-infected dairy herd and free-ranging wildlife species, such as pudu in the Los Ríos region, Chile. Since interspecies transmission of Map and other pathogens from livestock to pudu has already been demonstrated, the results from this study suggest that this free-ranging wildlife specie, inhabiting a dairy district in southern Chile, might represent another case of spillover host.

O agente etiológico da paratuberculose é o Mycobacterium avium subsp. paratuberculosis (Map). No Chile, já foi gerada informação do isolamento do Map em ruminantes domésticos e em algumas espécies selvagens, porém essa informação deve ser expandida a outras espécies. O presente estudo está focado na espécie selvagem herbívora, o Pudu (Pudu puda), que é considerado um dos cervos menos conhecidos da América do Sul, e que está em extinção. Essa espécie compartilha as pastagens com o gado no sul do Chile, local do país onde está concentrada a maior parte do rebanho leiteiro. Foram obtidas amostras de 3 pudus de uma fazenda de gado leiteiro, onde previamente havia sido confirmada a infecção por Map em bovinos. Os três pudus eliminavam a bactéria nas fezes, e os isolados fecais foram do mesmo tipo do Map relatado para os bovinos. Este estudo representa o primeiro relato de caso de isolamento do Map em pudu em vida silvestre. Também é a primeira associação documentada entre um rebanho leiteiro infectado com Map e a infecção de uma espécie silvestre de vida livre, tal como o pudu na região de Los Ríos, no Chile. A transmissão interespécies do Map, do mesmo modo que de outros patógenos de ruminantes para o pudu, já foi demonstrada, assim os resultados deste estudo sugerem que essa espécie de vida extensiva, que habita a mesma região leiteira no sul do Chile, pode representar mais um caso de repercussão ao hospedeiro.

Antecedente de agresión sexual y su asociación con conductas de riesgo en adolescentes consultantes en un centro de atención en salud sexual y reproductiva / History of sexual aggression and its association with risk behavior in adolescents consulting a focus on sexual and reproductive health

Antecedentes: La mayoría de los programas de salud reproductiva en Chile operan bajo la premisa de que todas las mujeres y en especial las adolescentes están o han estado comprometidas en relaciones sexuales consensuales, y no consideran que muchas de ellas pueden ser sobrevivientes de agresión sexual y pueden presentar necesidades diferentes en salud sexual y reproductiva. Objetivo: Examinar cuáles conductas de riesgo y variables sociodemográficas y familiares están asociadas al antecedente de agresión sexual en adolescentes consultantes en un centro de atención en salud sexual y reproductiva. Método: Estudio analítico de corte transversal. La información fue recolectada en la primera consulta a 3.064 adolescentes mujeres entre 12 y 19 años, atendidas en un centro de salud sexual y reproductiva en el período 2003-2010. Se usó regresión logística para identificar los factores asociados a la agresión sexual. Resultados: Un 22,7 por ciento reportó antecedente de agresión sexual. Las conductas de riesgo asociadas al antecedente de agresión sexual fueron: inicio de la actividad sexual bajo coerción o bajo efectos del alcohol, mayor número de relaciones afectivas y parejas sexuales, menor edad al inicio de la actividad sexual, menor promedio de notas, mayor consumo de cigarrillo, de alcohol y drogas, y menor edad al inicio del consumo de drogas. Conclusión: El antecedente de agresión sexual deja a las mujeres expuestas a riesgos en la salud sexual y reproductiva, por lo que los equipos de salud debieran ser capaces de detectar estas problemáticas para poder intervenir en forma adecuada y eficaz.

Background: Most of reproductive health programs in Chile operate under the premise that women and adolescent girls in particular, are or have been engaged in consensual sex and do not consider that many of them may be survivors of sexual abuse, and may have different needs in sexual and reproductive health. Objective: Determine which risk behaviors and familial variables are associated with sexual aggression history in adolescents consulting at sexual and reproductive health center. Method: Cross-sectional analytical study. The information was gathered from a structured interview applied in the first consultation to 3,064 adolescent girls between 12 and 19 years, who attended a sexual and reproductive health centre for the period 2003-2010. Logistic regression was used to identify factors associated with sexual assault. Results: A 22.7 percent reported sexual assault history. Risk behaviors associated with sexual aggression were: onset of sexual activity forced or under influence of alcohol, as many relationships and sexual partners, younger age at onset of sexual activity, lower grade point average, cigarette smoking, alcohol and drug use and younger age at onset of drug use. Conclusion: A history of sexual aggression leaves women at risk for sexual and reproductive health, so health teams should be able to detect these problems in order to intervene appropriately and effectively.

Adenosine mediates transforming growth factor-beta 1 release in kidney glomeruli of diabetic rats.

Up regulation of the transforming growth factor-beta 1 (TGF-beta1) axis has been recognized as a pathogenic event for progression of glomerulosclerosis in diabetic nephropathy. We demonstrate that glomeruli isolated from diabetic rats accumulate up to sixfold more extracellular adenosine than normal rats. Both decreased nucleoside uptake activity by the equilibrative nucleoside transporter 1 and increased AMP hydrolysis contribute to raise extracellular adenosine. Ex vivo assays indicate that activation of the low affinity adenosine A2B receptor subtype (A2BAR) mediates TGF-beta1 release from glomeruli of diabetic rats, a pathogenic event that could support progression of glomerulopathy when the bioavailability of adenosine is increased.

Correlación de las curvas Doppler de arterias uterinas con el desarrollo puberal de los genitales internos de niñas y adolescentes: experiencia en un servicio de imagenología pediátrico / Correlation of uterine artery Doppler patterns and the development of the internal genitalia of girls and adolescents: experience in a pediatric imaging department

Ultrasound allows evaluate in girls, the internal genitals development and their follow up during puberty. Doppler of the uterine arteries (UA) has demonstrated be a complementary parameter to detect the onset of puberty. Objective: To show through our experience, the correlation between the internal genital development and the Doppler of UA morphology in girls and adolescents. We analyzed in 84 ultrasounds (US); uterine morphology and the relation body/cervix, endometrial thickness, ovarian volume and the pattern of Doppler UA. We obtained a relationship between the anatomic changes usually studied and the patterns of the Doppler UA, since childhood to puberty. Conclusion: The diastolic flow changes in the UA can be complementary for the diagnosis of the degree of puberty.

El ultrasonido permite la evaluación del desarrollo de los genitales internos en las niñas y seguimiento a través de la pubertad. La curva del Doppler de arterias uterinas (AU) ha demostrado ser un parámetro complementario en la detección del inicio de la pubertad.Objetivo: mostrar la correlación del desarrollo de los genitales internos, con la morfología de las curvas Doppler de AU en niñas y adolescentes a través de nuestra experiencia. Analizamos en 85 ultrasonidos (US); morfología uterina, relación cuerpo/cervix, grosor endometrial, volumen ovárico y morfología de la curva del Doppler de AU. Constatamos una asociaciónentre los cambios morfológico estudiados habitualmente con los distintos patrones de las curvas del Doppler desde la niñez a la pubertad. Conclusión: Los cambios en el flujodiastólico de las arterias uterinas permiten complementar el diagnóstico del grado de progreso de la pubertad.

Modeling texture kinetics during thermal processing of potato products.

A kinetic model based on 2 irreversible serial chemical reactions has been proposed to fit experimental data of texture changes during thermal processing of potato products. The model links dimensionless maximum force F*(MAX) with processing time. Experimental texture changes were obtained during frying of French fries and potato chips at different temperatures, while literature data for blanching/cooking of potato cubes have been considered. A satisfactory agreement between experimental and predicted values was observed, with root mean square values (RMSs) in the range of 4.7% to 16.4% for French fries and 16.7% to 29.3% for potato chips. In the case of blanching/cooking, the proposed model gave RMSs in the range of 1.2% to 17.6%, much better than the 6.2% to 44.0% obtained with the traditional 1st-order kinetics. The model is able to predict likewise the transition from softening to hardening of the tissue during frying.