Association of the superior semicircular canal and tegmen tympani dehiscences and its relationship with the pneumatisation of the temporal bone.

PURPOSE: To analyse the degree of pneumatisation of the temporal bone when there is an association between dehiscence of the superior semicircular canal and dehiscence of the tegmen tympani. MATERIALS AND METHODS: We analysed a retrospective CT study of 124 selected cases. A single inclusion criterion was applied: the presence of a dehiscence of the tegmen tympani. On the other hand, the degree of temporal pneumatisation was assessed by axial and coronal planes, and has been divided into the following grades O, I, II and III, according to the status and relationship of the mastoid, the bony labyrinth, the petrous segment of the carotid canal and sigmoid sinus. RESULTS: Of the 124 cases studied, 35 (28.2%) presented both dehiscences. In 26 of the 35 (47.3%), grade II pneumatisation, 4 (14,8%), grade I, and 5 (11,9%) grade III was observed, with a statistically significant relationship (p < 0.001). On the other hand, we did not find a significant relationship when relating both dehiscences in any age or sex group. However, when relating the degree of pneumatisation to sex, among those with grade III pneumatisation, the proportion of men (52.4%) was significantly higher than that of women (47.6%) (p = 0.017). CONCLUSION: We have detected a statistically significant relationship between the coexistence of grade II pneumatisation and the presence of both dehiscences in the temporal bone.

Differential effects of 3,5-T2 and T3 on the gill regeneration and metamorphosis of the Ambystoma mexicanum (axolotl).

Thyroid hormones (THs) regulate tissue remodeling processes during early- and post-embryonic stages in vertebrates. The Mexican axolotl (Ambystoma mexicanum) is a neotenic species that has lost the ability to undergo metamorphosis; however, it can be artificially induced by exogenous administration of thyroxine (T4) and 3,3',5-triiodo-L-thyronine (T3). Another TH derivative with demonstrative biological effects in fish and mammals is 3,5-diiodo-L-thyronine (3,5-T2). Because the effects of this bioactive TH remains unexplored in other vertebrates, we hypothesized that it could be biologically active in amphibians and, therefore, could induce metamorphosis in axolotl. We performed a 3,5-T2 treatment by immersion and observed that the secondary gills were retracted, similar to the onset stage phenotype; however, tissue regeneration was observed after treatment withdrawal. In contrast, T4 and T3 immersion equimolar treatments as well as a four-fold increase in 3,5-T2 concentration triggered complete metamorphosis. To identify the possible molecular mechanisms that could explain the contrasting reversible or irreversible effects of 3,5-T2 and T3 upon gill retraction, we performed a transcriptomic analysis of differential expression genes in the gills of control, 3,5-T2-treated, and T3-treated axolotls. We found that both THs modify gene expression patterns. T3 regulates 10 times more genes than 3,5-T2, suggesting that the latter has a lower affinity for TH receptors (TRs) or that these hormones could act through different TR isoforms. However, both TH treatments regulated different gene sets known to participate in tissue development and cell cycle processes. In conclusion, 3,5-T2 is a bioactive iodothyronine that promoted partial gill retraction but induced full metamorphosis in higher concentrations. Differential effects on gill retraction after 3,5,-T2 or T3 treatment could be explained by the activation of different clusters of genes related with apoptosis, regeneration, and proliferation; in addition, these effects could be initially mediated by TRs that are expressed in gills. This study showed, for the first time, the 3,5,-T2 bioactivity in a neotenic amphibian.

The importance of thyroid hormone signaling during early development: Lessons from the zebrafish model.

The zebrafish is an optimal experimental model to study thyroid hormone (TH) involvement in vertebrate development. The use of state-of-the-art zebrafish genetic tools available for the study of the effect of gene silencing, cell fate decisions and cell lineage differentiation have contributed to a more insightful comprehension of molecular, cellular, and tissue-specific TH actions. In contrast to intrauterine development, extrauterine embryogenesis observed in zebrafish has facilitated a more detailed study of the development of the hypothalamic-pituitary-thyroid axis. This model has also enabled a more insightful analysis of TH molecular actions upon the organization and function of the brain, the retina, the heart, and the immune system. Consequently, zebrafish has become a trendy model to address paradigms of TH-related functional and biomedical importance. We here compilate the available knowledge regarding zebrafish developmental events for which specific components of TH signaling are essential.

Chronic atrazine exposure increases the expression of genes associated with GABAergic and glutamatergic systems in the brain of male albino rat.

The herbicide atrazine (ATR; 2-chloro-4-ethylamino-6-isopropylamino-s-triazine) is widely used to destroy grasses and broadleaf weeds in crops and some fruits. Studies in rodents have shown that acute, repeated or chronic exposure to ATR is associated with alterations in the nigrostriatal dopaminergic pathway, whereas its effects on GABAergic and glutamatergic pathways have only recently been reported. Sprague-Dawley male rats were exposed daily to 1 or 10 mg ATR/kg of BW for 13 months to evaluate the ATR effects on GABAergic and glutamatergic systems. At the end of the ATR treatment, the levels of mRNA of several genes involved in the production, vesiculation, reuptake, and receptors of GABA and Glu in the striatum (STR), nucleus accumbens (NAcc), prefrontal cortex (PFC), ventral midbrain (vMID) and hippocampus (HIPP) were evaluated by absolute qPCR. For the GABAergic genes, increased expression of GAD67 and Slc32a1 in STR and/or vMID in rats exposed to 1 and/or 10 mg ATR were detected. With regard to the expression of genes involved in the glutamatergic system, Slc17a6 and Grin1 in HIPP of rats exposed to 1 and/or 10 mg ATR, increased as was Gria1 in STR and PFC in the group exposed to 1 mg ATR. In the same fashion, Slc1a3 expression and MGLUR1 increased in STR of rats exposed to 1 and 10 mg ATR groups. The expression of the glutaminases gls (variants 1 and 2) was greater in STR, NAcc, HIPP, and PFC of rats exposed to 1 and/or 10 mg ATR. These findings show that the GABAergic and, especially glutamatergic systems are targets of ATR exposure.

Influence of Baseline Physical Activity as a Modifying Factor on COVID-19 Mortality: A Single-Center, Retrospective Study.

INTRODUCTION: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes a severe respiratory disease with a 3% global mortality. In the absence of effective treatment, controlling of risk factors that predispose to severe disease is essential to reduce coronavirus disease 2019 (COVID-19) mortality. Large observational studies suggest that exercise can reduce the risk of all-cause and disease-specific mortality. The aim of this study was to analyze the influence of the baseline physical activity level on COVID-19 mortality METHODS: This is a retrospective cohort study that included patients between 18 and 70 years old, diagnosed with COVID-19 and hospitalized in our center between February 15 and April 15, 2020. After discharge all the patients included in the study were contacted by telephone. Baseline physical activity level was estimated using the Rapid Assessment of Physical Activity Scale questionnaire and patients were divided into two groups for comparison: sedentary patients (group 1) and active patients (group 2). RESULTS: During the study period 552 patients were admitted to our hospital and met the inclusion criteria. Global mortality in group 1 was significantly higher than in group 2 (13.8% vs 1.8%; p < 0.001). Patients with a sedentary lifestyle had increased COVID-19 mortality independently of other risk factors previously described (hazard ratio 5.91 (1.80-19.41); p = 0.003). CONCLUSION: A baseline sedentary lifestyle increases the mortality of hospitalized patients with COVID-19. This finding may be of great utility in the prevention of severe COVID-19 disease.

Biological removal of hexavalent chromium: evaluation of the metabolic activity of native and Cr(VI)-acclimated activated sludge using a respirometric method.

Hexavalent chromium becomes in one of the tops internationally concern environmental issues due to its wide usage in several industrial activities. There are two stable oxidation states of chromium in the environment which differ significantly on its toxicity; Cr(III) has lower solubility, mobility and lesser biological toxicity in comparison with Cr(VI). While Cr(VI) is a well-known carcinogen, Cr(III) is an essential dietary element. For this reason, most technologies focus attention on the reduction of Cr(VI) to Cr(III). On this context, the ability of microorganisms to reduce Cr(VI) to Cr(III) has gained attention. The objectives of the present work were to analyze the effect of Cr(VI) on the activated sludge community in a continuous reactor, and to evaluate the differences on the metabolic activity of native (NAS) and Cr(VI)-acclimated activated sludge (CrAAS) using a respirometric method. Results showed that the activated sludge community had the capability to acclimate to the presence of Cr(VI). On the other hand, the increase of the initial Cr(VI) concentration from 0 to 100 mgCr/L leads to a decrease in the specific exogenous respiration rate (qEx ) values, but this reduction was more noticeably in the case of NAS in comparison with CrAAS. The respirometric curves were well described by the proposed mathematical model. It was concluded that the CrAAS tolerated a Cr(VI) concentration about one order of magnitude higher than NAS, which was positively reflected in the respiration rate first-order decay constant (kd ), the specific maximum exogenous respiration rate (qExm ), and the observed oxidation coefficient (YO/S ) values.

Bone Marrow Culture Yield for the Diagnosis of Opportunistic Diseases in Patients with AIDS and Disseminated Kaposi Sarcoma.

BACKGROUND: Disseminated Kaposi sarcoma (DKS) is present in patients with advanced HIV infection in whom co-infection with other opportunistic pathogens can occur. Bone marrow (BM) aspirate and biopsy comprise a robust diagnostic tool in patients with fever, cytopenias, and abnormal liver tests. However, the yield in patients with DKS has not been determined. OBJECTIVE: The aim of this study was to evaluate the utility of BM aspirate and biopsy in patients with DKS. METHODS: We included 40 male patients with a recent diagnosis of DKS. BM aspirate and biopsy was performed as part of the workup to rule out co-infections. RESULTS: In four patients, Mycobacterium avium complex (MAC) was recovered from culture. In other four patients, intracellular yeasts were observed in the Grocott stain, diagnosed as Histoplasma. The yield of BM was calculated in 20%. Only 12 patients (30%) had fever and 11 (27.5%) had pancytopenia. Alkaline phosphatase (ALP) above normal values and C-reactive protein (CRP) were higher in patients with positive results for BM than in those with negative results (63% vs. 21.9%, and 3.0 vs. 1.2 mg/L; p = 0.03 in both comparisons). No differences were found when complete blood-count abnormalities were compared. CONCLUSION: We recommend performing a BM aspirate for stains, culture, and biopsy in all HIV patients with DKS, as this will permit the early diagnosis of co-infections and prevent further complications in those who receive chemotherapy.

Mapping biogeochemically active zones in landfills with induced polarization imaging: The Heferlbach landfill.

In this study, we investigate the applicability of the Induced Polarization (IP) imaging method to discriminate between biogeochemically active and inactive areas of a landfill. The elevated amount of degradable organic carbon in landfills results in the development of biogeochemical hot-spots associated with high rates of microbial activity and the generation of landfill gas and leachate as metabolic products. Our results demonstrate that the electrical conductivity is mainly sensitive to the increase in the fluid conductivity associated to leachate production and migration. Whereas images of the polarization effect, expressed in terms of the imaginary component (σ″) or the phase of the complex conductivity (ϕ), reveal the potential to characterize variations in the architecture and biogeochemical activity of the landfill. Correspondingly, biogeochemically active zones (leachable TOC contents above 1500 mg/kg dry waste) are related to high polarization values (σ″ > 10 mS/m, ϕ > 40 mrads), whereas low leachable TOC contents (<300 mg/kg dry waste) in the inactive areas are characterized by low polarization values (σ″ < 1 mS/m, 10 < Ï• < 25). Additionally, landfill sections corresponding to construction and demolition waste (CDW), associated to negligible TOC content, exhibit the lowest polarization response (σ″ < 0.1 mS/m, ϕ < 15). We prove that IP imaging is a well-suited method for landfill investigations that permits an improved characterization of landfill geometry, variation in waste composition, and the discrimination between biogeochemically active and inactive zones.

Super large cardiac hemangioma in right atrium and inferior vena cava: case report.

BACKGROUND: Cardiac hemangiomas are rare cardiac neoplasia usually diagnosed in autopsies, from being asymptomatic to debuting with sudden death. The largest hemangioma published in the literature is of 130 mm size, we present the following case of a successful cardiac hemangioma excision of 280 × 35 mm in size, diagnosed due to recurrent cardiac symptoms. CASE PRESENTATION: A 48-year-old female patient, Jehovah's Witness, with no previous diagnoses, is admitted due to recurrent syncopal episodes in the previous months. A transthoracic echocardiogram diagnosed a tumor in the right atrium and inferior vena cava producing a diastolic right ventricular, with preservation of the left ventricular ejection fraction at 55%. Given the high mortality risk, a surgical intervention was performed immediately. Successful excision was completed confirming a 280 × 35 mm mass without any complications, consistent with hemangioma on histopathology. Postoperative recovery showed no recurrence or complications. CONCLUSIONS: Cardiac hemangiomas are rare and its clinical course can be varied from patient to patient. We present excision of a large cardiac mass with a high mortality risk due to its size and the patient's spiritual beliefs.

3,5-T2 and 3,3',5-T3 Regulate Cerebellar Thyroid Hormone Signalling and Myelin Molecular Dynamics in Tilapia.

In contrast to mammalian adults, myelination in teleosts occurs throughout their lifespan and most of the progenitor cells are originated in the cerebellum. To understand the role that thyroid hormones (THs) play in juvenile cerebellar myelination in teleosts, we identified and localised the expression of genes involved in TH signalling (mct8, oatp1c1, dio2, dio3, thraa and l-thrb1) and analysed the effects of the two bioactive THs, T2 and T3, upon their regulation, as well as upon some structural components of the myelination process. Ex vivo approaches using organotypic cerebellar cultures followed by FISH and qPCR showed gene-specific localisation and regulation of TH signalling genes in the cerebellar nuclei. In vivo approaches using methimazole (MMI)-treated juvenile tilapias replaced with low doses of T3 and T2 showed by immunofluorescence that myelin fibres in the cerebellum are more abundant in the granular layer and that their visible size is reduced after MMI treatment but partially restored with TH replacement, suggesting that low doses of TH promote the re-myelination process in an altered condition. Together, our data support the idea that T2 and T3 promote myelination via different pathways and prompt T2 as a target for further analysis as a promising therapy for hypomyelination.

Interdependence between the aerobic degradation of BPA and readily biodegradable substrates by activated sludge in semi-continuous reactors.

The objective of the present work was to analyze the interrelationship between the aerobic degradation of BPA and readily biodegradable substrates by activated sludge (AS) in semi-continuous reactors (SCRs). AS were obtained from three SCRs fed with glucose, acetate or peptone. AS from these reactors were used as inocula for three SCRs that were fed with each biogenic substrate, and for three SCRs that were fed with the biogenic substrate and BPA. In all cases, dissolved organic carbon (DOC), BPA, total suspended solids (TSS) and respirometric measurements were performed. Although BPA could be removed in the presence of all the tested substrates, AS grown on acetate exhibited the longest acclimation to BPA. Reactors fed with peptone attained the lowest TSS concentration; however, these AS had the highest specific BPA degradation rate. Specific DOC removal rates and respirometric measurements demonstrated that the presence of BPA had a negligible effect on the removal of the tested substrates. A mathematical model was developed to represent the evolution of TSS and DOC in the SCRs as a function of the operation cycle. Results suggest that the main effect of BPA on AS was to increase the generation of microbial soluble products. This work helps to understand the relationship between the biodegradation of BPA and readily biodegradable substrates.

Babesia spp. no líquido peritoneal em cão com ascite - relato de caso / Babesia spp. in the peritoneal fluid in dog with ascites - case report

Babesia canis é um protozoário cosmopolita que parasita eritrócitos de cães domésticos e selvagens. O diagnóstico é realizado mediante a observação direta do microrganismo em hemácias no esfregaço de sangue periférico, métodos sorológicos e técnicas moleculares. O objetivo deste trabalho é relatar pela primeira vez a presença de merozoítos de Babesia spp. no líquido peritoneal de um cão com ascite. No Hospital Veterinário da Universidade Federal de Viçosa, foi atendido um cão, macho, sem raça definida, de sete meses de idade, com histórico de emaciação, apatia e abaulamento abdominal. No exame físico, foram evidenciadas mucosas hipocoradas, ascite, sopro sistólico grau IV/V e taquipneia. Nos exames laboratoriais, evidenciou-se anemia normocítica/normocrômica, trombocitopenia e hipoproteinemia. No esfregaço sanguíneo, foram observadas estruturas intraeritrocitárias compatíveis com Babesia spp. A avaliação do líquido ascítico foi compatível com transudato modificado e observaram-se inúmeras estruturas intra e extracelulares compatíveis com merozoítas de Babesia spp. A presença de microrganismos intra e extracelular poderia estar relacionada a uma lesão no baço com extravasamento do conteúdo para a cavidade abdominal. A coleta do líquido peritoneal pode ser uma alternativa para o diagnóstico de babesiose quando o animal com suspeita da infecção apresentar ascite.(AU)

Babesia canis is a cosmopolitan protozoan that parasites erythrocytes of domestic and wild dogs. The diagnosis is performed by direct observation of the microorganism in red blood cells in the peripheral blood smear, serological methods and molecular techniques. The aim of this work is to report for the first time the presence of merozoites of Babesia spp. in the peritoneal fluid of a dog with ascites. At the Veterinary Hospital of the Federal University of Viçosa was attended a Mixed-breed seven month old dog, male, with history of emaciation, apathy and abdominal bulging. Pale mucous membranes, ascites, grade IV/V systolic murmur and tachypnea were evidenced in the physical examination. Laboratory tests revealed normocytic/normochromic anemia, thrombocytopenia, and hypoproteinemia. Intra-erythrocyte structures compatible with Babesia spp. were observed in the blood smear. The evaluation of the ascites fluid was compatible with modified transudate where numerous intra and extracellular structures compatible with Babesia spp. merozoites were observed. The presence of intra and extracellular microorganisms could be related to an injury of the spleen with extravasation of the contents into the abdominal cavity. Collection of the peritoneal fluid may be an alternative for the diagnosis of babesiosis when the animal with suspected infection has ascites.(AU)

Modelo Matemático de VIH bajo la Administración de un Antirretroviral / HIV Mathematical Model considering Antiretroviral Administration

RESUMEN En este trabajo se propone un modelo matemático consistente de cuatro ecuaciones diferenciales ordinarias que describen la evolución del VIH en un individuo seropositivo y el efecto de un antirretroviral en el proceso de replicación del virus en las células T CD4+. Con el propósito de determinar la efectividad del medicamento en el largo plazo se analizan los casos con y sin el tratamiento antirretroviral para observar el efecto en la población de células T CD4+ sanas e infectadas. Con el modelo matemático propuesto se encuentra un caso en el cual el tratamiento antirretroviral permite mantener una concentración de T CD4+ no infectadas clínicamente saludable en el organismo. Mediante la aplicación del método de Conjuntos Compactos Invariantes se establecen los límites máximos para las poblaciones de células sanas e infectadas, así como la concentración del VIH libre en el organismo. Finalmente, se realizan simulaciones numéricas para ilustrar los resultados en el plano temporal, se grafican las soluciones del sistema y los límites superiores obtenidos, estos permiten observar el valor máximo que pueden llegar a alcanzar las poblaciones de células sanas, las infectadas y la concentración de VIH en el torrente sanguíneo.

ABSTRACT In this work, we present a proposal of a mathematical model of four ordinary differential equations that describe the evolution of HIV in an HIV-positive individual and the effect of an antiretroviral in the process of virus replication in CD4+ T cells. In order to determine the long-term effectiveness of the drug, the cases with and without antiretroviral treatment are analyzed to observe the effect on the population of healthy and infected CD4+ T cells. With our mathematical model, we are able to obtain a case where the antiretroviral allows a clinically healthy concentration of uninfected CD4+ T cells. Additionally, by applying the Compact Invariant Sets method we determine maximum values for the concentration of free HIV and both cells populations, healthy and infected. Finally, we perform numerical simulations in order to illustrate our results in the temporal plane, we plot the solutions of the system and their corresponding upper bounds, the latter allow us to define the maximum values of the HIV concentration in the bloodstream and the infected and healthy cells populations.

Differential transcriptome regulation by 3,5-T2 and 3',3,5-T3 in brain and liver uncovers novel roles for thyroid hormones in tilapia.

Although 3,5,3'-triiodothyronine (T3) is considered to be the primary bioactive thyroid hormone (TH) due to its high affinity for TH nuclear receptors (TRs), new data suggest that 3,5-diiodothyronine (T2) can also regulate transcriptional networks. To determine the functional relevance of these bioactive THs, RNA-seq analysis was conducted in the cerebellum, thalamus-pituitary and liver of tilapia treated with equimolar doses of T2 or T3. We identified a total of 169, 154 and 2863 genes that were TH-responsive (FDR < 0.05) in the tilapia cerebellum, thalamus-pituitary and liver, respectively. Among these, 130, 96 and 349 genes were uniquely regulated by T3, whereas 22, 40 and 929 were exclusively regulated by T2 under our experimental paradigm. The expression profiles in response to TH treatment were tissue-specific, and the diversity of regulated genes also resulted in a variety of different pathways being affected by T2 and T3. T2 regulated gene networks associated with cell signalling and transcriptional pathways, while T3 regulated pathways related to cell signalling, the immune system, and lipid metabolism. Overall, the present work highlights the relevance of T2 as a key bioactive hormone, and reveals some of the different functional strategies that underpin TH pleiotropy.

Monitoring the biodegradability of bisphenol A and its metabolic intermediates by manometric respirometry tests.

As a result of its wide usage in the production of polycarbonate plastics and epoxy resins, bisphenol A (BPA) is commonly detected in wastewaters. Recently, BPA became a major concern because its adverse effects as an endocrine disruptor. In this work, the biodegradation kinetics of BPA and its metabolic intermediates 4-hydroxyacetophenone (4HAP), 4-hydroxybenzaldehyde (4HB) and 4-hydroxybenzoic acid (4HBA) by BPA-acclimated activated sludge was studied using manometric respirometry (BOD) tests. For all the tested compounds, BOD curves exhibited two phases. In the first one, a fast increase of the oxygen consumption (OC) due to the active oxidation of the substrate was obtained. Then, when the substrate was exhausted, the endogenous respiration produced a slower increase of OC. A standard Monod-model with biomass growth was used to represent the OC profiles as a function of time. For all the tested compounds, a good agreement between the proposed model and the experimental data was obtained. According to their biodegradation rates, the tested compounds can be ordered as follows: BPA < 4HAP â‰ª 4HB < 4HBA. Because the oxidation rate of BPA by BPA-acclimated activated sludge limits the rate of the whole biodegradation pathway, the accumulation of metabolic intermediates 4HAP, 4HB, and 4HBA would be negligible. To calculate the dissolved oxygen (DO) concentration (C) during the BOD tests, the oxygen transfer coefficient (kLa) of the BOD bottles was obtained using the sulfite method. Finally, a simple procedure to calculate the minimum DO concentration (Cmin) based on BOD data was developed. Calculation results demonstrated that under the tested conditions, C values were high enough as not to be the limiting substrate for the microbial growth.

Attitudes Toward Organ Donation and Transplantation in Guanajuato, Mexico.

BACKGROUND: Chronic diseases have become a main cause of morbidity and mortality provoking function loss in organs. Quality of life is poor and expensive with replacement therapy. Transplantation offers a higher survival rate and a better life; however, the donation rate in Mexico is low, making it important to know the opinion of the population. METHODS: Six hundred forty-two people in Guanajuato, Mexico, (>15 years old) were enrolled. Demographic characteristics, education, religion, organ donation, and transplantation attitudes were evaluated. RESULTS: Donation attitudes in life or death were: very willing to donation (82.8% vs 61.5%), refuse to donate (12.7% vs 29.4%), and undecided (4.5% vs 9.1%). Reasons for donation were: altruism (63%), being useful to someone (28.6%), and empathy (7.1%). Negative causes were: personal beliefs (35.6%), fear (23.7%), and ignorance or "I don't know the recipient" (18.5%). Finally, 94.5% of the population is willing to receive a transplant if they need it. CONCLUSIONS: Guanajuato has a high tendency to donate their own organs, but less to donate from a family member. Refusal to donate has originated from lack/misinformation that people received from health professionals. Although most people are willing to donate, this is not reflected in donation rates. To be able to make this intention reality, we must create educational models for health care personnel that will allow them to transmit proper information to the population.

Mechanical properties derived from phase separation in co-polymer hydrogels.

Hydrogels can be synthesized with most of the properties needed for biomaterials applications. Soft, wettable, and highly permeable gels with a practically unlimited breadth of chemical functionalities are routinely made in the laboratory. However, the ability to make highly elastic and durable hydrogels remains limited. Here we describe an approach to generate stretchy, durable hydrogels, employing a high polymer-to-crosslink ratio for extensibility, combined with an aggregating copolymer phase to provide stability against swelling. We find that the addition of aggregating co-polymer can produce a highly extensible gel that fails at 1000% strain, recovers from large strains within a few minutes, maintains its elasticity over repeated cycles of large amplitude strain, and exhibits significantly reduced swelling. We find that the gel׳s enhanced mechanical performance comes from a kinetically arrested structure that arises from a competition between the disparate polymerization rates of the two components and the aggregation rate of the unstable phase. These results represent an alternative strategy to generating the type of stretchy elastomer-like hydrogels needed for biomedical technologies.

ARHI (DIRAS3)-mediated autophagy-associated cell death enhances chemosensitivity to cisplatin in ovarian cancer cell lines and xenografts.

Autophagy can sustain or kill tumor cells depending upon the context. The mechanism of autophagy-associated cell death has not been well elucidated and autophagy has enhanced or inhibited sensitivity of cancer cells to cytotoxic chemotherapy in different models. ARHI (DIRAS3), an imprinted tumor suppressor gene, is downregulated in 60% of ovarian cancers. In cell culture, re-expression of ARHI induces autophagy and ovarian cancer cell death within 72 h. In xenografts, re-expression of ARHI arrests cell growth and induces autophagy, but does not kill engrafted cancer cells. When ARHI levels are reduced after 6 weeks, dormancy is broken and xenografts grow promptly. In this study, ARHI-induced ovarian cancer cell death in culture has been found to depend upon autophagy and has been linked to G1 cell-cycle arrest, enhanced reactive oxygen species (ROS) activity, RIP1/RIP3 activation and necrosis. Re-expression of ARHI enhanced the cytotoxic effect of cisplatin in cell culture, increasing caspase-3 activation and PARP cleavage by inhibiting ERK and HER2 activity and downregulating XIAP and Bcl-2. In xenografts, treatment with cisplatin significantly slowed the outgrowth of dormant autophagic cells after reduction of ARHI, but the addition of chloroquine did not further inhibit xenograft outgrowth. Taken together, we have found that autophagy-associated cancer cell death and autophagy-enhanced sensitivity to cisplatin depend upon different mechanisms and that dormant, autophagic cancer cells are still vulnerable to cisplatin-based chemotherapy.

Simultaneous biodegradation of bisphenol A and a biogenic substrate in semi-continuous activated sludge reactors.

In this work, the simultaneous degradation of BPA and cheese whey (CW) in semi-continuous activated sludge reactors was studied. The acclimation process and microbial growth on BPA, CW and BPA + CW were analyzed. In addition, the effect of increasing CW concentration on the BPA degradation by acclimated activated sludge was also studied. In order to reduce the factors involved in the analysis of the simultaneous degradation of BPA and CW, the effect of bisphenol A (BPA) on activated sludge not previously exposed to BPA (native activated sludge) was studied. Results demonstrate that BPA concentrations lower than 40 mg l(-1) had a negligible effect on the growth of native activated sludge. In the semi-continuous reactors, the presence of CW increased the acclimation time to 40 mg l(-1) of BPA. Once the capability of degrading BPA was acquired, the removal of BPA was not affected by the presence of CW. Increasing the CW concentration did not affect the removal of BPA by the acclimated activated sludge. Additionally, the CW consumption was not modified by the presence of BPA. Kinetic and stoichiometric coefficients reported in the present work can be useful in developing mathematical models to describe the simultaneous aerobic biodegradation of a biogenic substrate, such as CW, and BPA by activated sludge.

Generalización e inferencia: un acercamiento a su compresión desde tres enfoques / Generalization and inference: an understanding based on three approaches

Se trata de una reflexión que busca poner en discusión los diferentes significados que pueden adquirir los conceptos de generalización e inferencia, de acuerdo con el enfoque o perspectiva desde el cual se pretendan utilizar. Para este propósito, en primer lugar, se pone en consideración la importancia y el uso que se ha dado a estos conceptos en el campo de la epidemiología clásica-moderna, especialmente para definir asuntos de validez interna y externa y para la formulación de hipótesis. Seguidamente, se presentan las principales argumentaciones que al respecto defiende Clifford Geertz desde su perspectiva epistemológica de la etnografía interpretativista y de acuerdo con su concepción teórica de la cultura. Posteriormente, se presentan las ideas que sustenta Juan Samaja desde su enfoque epistemológico y metodológico para la investigación en salud, abogando principalmente por el razonamiento abductivo, y no sólo el inductivo y el deductivo que han sido privilegiados en los estudios lógicos. Por último se presenta una discusión y unas conclusiones destacando que en estas tres perspectivas la salud pública tiene una oportunidad para enriquecer sus procesos de generación de nuevo conocimiento y para comprender de mejor manera las condiciones de salud y de bienestar colectivo.

This paper is a reflection which seeks to stimulate discussion and debate concerning the different meanings that the concepts of generalization and inference can take on, based on the approach or perspective that is being employed. For this purpose the importance and usage which has been accorded to these concepts within the field of classic-modern epidemiology is taken into consideration, especially in order to define internal and external validity issues and to formulate hypotheses. Next the main arguments are presented and are defended by Clifford Geertz from his epistemological perspective of interpretive ethnography and based on his theoretical conception of culture. Subsequently the ideas maintained by Juan Samaja are presented from his epistemological and methodological approach for research into health, advocating primarily for abductive reasoning, and not simply inductive and deductive, which have until now been privileged in logic studies. Finally a discussion and conclusions are presented, highlighting that from these three perspectives public health has the opportunity to expand its new knowledge generation processes and to better understand the conditions for good collective health and wellbeing.