Adsorption kinetics and Box-Behnken design optimization for organic dyes on tungsten oxide.

Transition metal oxides have been applied to degrade organic dyes found in water bodies via photocatalysis. To do it, however, is essential that the dye molecules adsorb onto the metal oxide surface. Thus, optimizing the adsorption capacity of the adsorbent increases the probability of reaction between oxidation radicals and organic dye molecules and maximizes the effectiveness per gram of photocatalyst. With this in mind, we studied the adsorption behavior of Methylene Blue (MB) and Acid Orange 7 (AO7), two commonly found pollutants, as a function of dilution's pH, WO3 load, and initial dye concentration. We found out that WO3 adsorbs up to 80% of MB at pH = 6, and 13% of AO7 at pH = 2, although it is unable to adsorb AO7 at the natural pH of the dye dilution. Assuming a pseudo-second order kinetics model for the analysis of the MB adsorption amount, we determined a rate constant k2 = 6 × 10-2(g · mg-1)/min for the adsorption process. We put forward a molecular model for adsorption, driven by concentration gradients and electrostatic interactions. Finally, from a statistical analysis, we determined that pH is the most significant factor for the adsorption of MB and AO7 on WO3, reinforcing the notion that electrostatic interactions are the main mechanism driving the adsorption process. The Box-Behnken design optimization also evinces the key playing role of WO3 load in the adsorption percentage of AO7 and let us establish the optimal load required to maximize adsorption.

Indocyanine green fluorescence angiography in colorectal surgery. First case series in Mexico.

INTRODUCTION AND AIM: Anastomosis leak occurs in 1-19% of colorrectal surgeries. Our objective was to present the first Mexican case series on colorrectal surgery using indocyanine green fluorescence angiography to evaluate perfusion prior to carrying out the anastomosis. MATERIALS AND METHODS: A retrospective, analytic, descriptive study was conducted. We studied the case records of consecutive patients that underwent colorrectal surgery with indocyanine green angiography performed by the same group of colorrectal surgeons. RESULTS: Twenty-one case records were reviewed. Eleven (52.3%) of the patients were women, mean patient age was 57 years (38-82), and mean body mass index was 25 kg/m2 (17-34). Fifteen (71.4%) patients were diagnosed with malignant disease. Indocyanine green angiography changed our therapeutic decision in three (14.2%) patients. Two colorrectal anastomoses (14.2%) were performed at fewer than 5 cm from the anal verge and 13 (61.9%) were performed at more than 5 cm from the anal verge. Three of the anastomoses were ileocolic (14.2%), two were coloanal (9.5%), and one was ileoanal (4.7%). There were six (28.5%) complications, no cases of anastomotic leak, and no complications associated with the use of indocyanine green. The mortality rate was 0%. CONCLUSION: The present case series is the first on colorrectal surgery conducted in Mexico using indocyanine green fluorescence angiography, with excellent results.

Indocyanine green fluorescence angiography in colorrectal surgery. First case series in Mexico. / Angiografía por fluorescencia con verde de indocianina para cirugía de colon y recto. Primera serie reportada en México.

INTRODUCTION AND AIM: Anastomotic leak occurs in 1-19% of colorrectal surgeries. Our objective was to present the first Mexican case series on colorrectal surgery using indocyanine green fluorescence angiography to evaluate perfusion prior to carrying out the anastomosis. MATERIALS AND METHODS: A retrospective, analytic, descriptive study was conducted. We studied the case records of consecutive patients that underwent colorrectal surgery with indocyanine green angiography performed by the same group of colorrectal surgeons. RESULTS: Twenty-one case records were reviewed. Eleven (52.3%) of the patients were women, mean patient age was 57 years (38-82), and mean body mass index was 25 kg/m2 (17-34). Fifteen (71.4%) patients were diagnosed with malignant disease. Indocyanine green angiography changed our therapeutic decision in three (14.2%) patients. Two colorrectal anastomoses (14.2%) were performed at fewer than 5 cm from the anal verge and 13 (61.9%) were performed at more than 5 cm from the anal verge. Three of the anastomoses were ileocolic (14.2%), two were coloanal (9.5%), and one was ileoanal (4.7%). There were six (28.5%) complications, no cases of anastomotic leak, and no complications associated with the use of indocyanine green. The mortality rate was 0%. CONCLUSION: The present case series is the first on colorrectal surgery conducted in Mexico using indocyanine green fluorescence angiography, with excellent results.

Regression models to predict the behavior of the coefficient of friction of AISI 316L on UHMWPE under ISO 14243-3 conditions.

Friction is the natural response of all tribosystems. In a total knee replacement (TKR) prosthetic device, its measurement is hindered by the complex geometry of its integrating parts and that of the testing simulation rig operating under the ISO 14243-3:2014 standard. To develop prediction models of the coefficient of friction (COF) between AISI 316L steel and ultra-high molecular weight polyethylene (UHMWPE) lubricated with fetal bovine serum dilutions, the arthrokinematics and loading conditions prescribed by the ISO 142433: 2014 standard were translated to a simpler geometrical setup, via Hertz contact theory. Tribological testing proceeded by loading a stainless steel AISI 316L ball against the surface of a UHMWPE disk, with the test fluid at 37 °C. The method has been applied to study the behavior of the COF during a whole walking cycle. On the other hand, the role of protein aggregation phenomena as a lubrication mechanism has been extensively studied in hip joint replacements but little explored for the operating conditions of a TKR. Lubricant testing fluids were prepared with fetal bovine serum (FBS) dilutions having protein mass concentrations of 5, 10, 20 and 36 g/L. The results were contrasted against deionized, sterilized water. The results indicate that even at protein concentration as low as 5 g/L, protein aggregation phenomena play an important role in the lubrication of the metal-on-polymer tribopair. The regression models of the COF developed herein are available for numerical simulations of the tribological behavior of the aforementioned tribosystem. In this case, surface stress rather than film thickness should be considered.

Serotonin inputs to the dorsal BNST modulate anxiety in a 5-HT1A receptor-dependent manner.

Serotonin (5-HT) neurons project from the raphe nuclei throughout the brain where they act to maintain homeostasis. Here, we study 5-HT inputs into the bed nucleus of the stria terminalis (BNST), a major subdivision of the extended amygdala that has been proposed to regulate responses to anxiogenic environments in humans and rodents. While the dorsal part of the BNST (dBNST) receives dense 5-HT innervation, whether and how 5-HT in the dBNST normally modulates anxiety remains unclear. Using optogenetics, we demonstrate that activation of 5-HT terminals in the dBNST reduces anxiety in a highly anxiogenic environment. Further analysis revealed that optogenetic inhibition of 5-HT inputs into the dBNST increases anxiety in a less anxiogenic environment. We found that 5-HT predominantly hyperpolarizes dBNST neurons, reducing their activity in a manner that can be blocked by a 5-HT1A antagonist. Finally, we demonstrate that activation of 5-HT1A receptors in the dBNST is necessary for the anxiolytic effect observed following optogenetic stimulation of 5-HT inputs into the dBNST. These data reveal that 5-HT release in the dBNST modulates anxiety-like behavior via 5-HT1A receptors under naturalistic conditions.

The coefficient of friction of UHMWPE along an entire walking cycle using a ball-on-disc tribometer under arthrokinematics and loading conditions prescribed by ISO 14243-3:2014.

The observation of tribological phenomena occurring in total knee replacement (TKR) simulators may be obscured by the intrinsic complexity of their operation: the dynamics and kinematics prescribed by the ISO 14243-3:2014 standard, and the geometry of the surfaces involved. On the other hand, evaluating the individual performance of the tribosystem elements may be carried out in simpler apparatuses. An experimental method is presented here, by means of which the arthrokinematics and loading conditions prescribed by the said standard are adapted to a ball-on-disc configuration in order to observe the behavior of the coefficient of friction along an entire walking cycle, using the contact point of an AISI 316L stainless steel ball rolling/sliding on an ultra-high molecular weight polyethylene (UHMWPE) disc, lubricated by a solution of fetal bovine serum, at 37°C. The method was tried on two different testing fluids prepared with protein concentrations of 20g/L, according to the said standard, and 36g/L, as received. The statistical model obtained for the behavior of the COF during the entire walking cycle may be used in numerical simulations of UHMWPE wear, under the conditions established by ISO 14243-3:2014.

Disruption of 5-HT1A function in adolescence but not early adulthood leads to sustained increases of anxiety.

Current evidence suggests that anxiety disorders have developmental origins. Early insults to the circuits that sub-serve emotional regulation are thought to cause disease later in life. Evidence from studies in mice demonstrate that the serotonergic system in general, and serotonin 1A (5-HT1A) receptors in particular, are critical during the early postnatal period for the normal development of circuits that subserve anxious behavior. However, little is known about the role of serotonin signaling through 5-HT1A receptors between the emergence of normal anxiety behavior after weaning, and the mature adult phenotype. Here, we use both transgenic and pharmacological approaches in male mice, to identify a sensitive period for 5-HT1A function in the stabilization of circuits mediating anxious behavior during adolescence. Using a transgenic approach we show that suppression of 5-HT1A receptor expression beginning in early adolescence results in an anxiety-like phenotype in the open field test. We further demonstrate that treatment with the 5-HT1A antagonist WAY 100,635 between postnatal day (P)35 and P50, but not at later timepoints, results in altered anxiety in ethologically based conflict tests like the open field test and elevated plus maze. This change in anxiety behavior occurs without impacting behavior in the more depression-related sucrose preference test or forced swim test. The treatment with WAY 100,635 does not affect adult 5-HT1A expression levels, but leads to increased expression of the serotonin transporter in the raphe, along with enhanced serotonin levels in both the prefrontal cortex and raphe that correlate with the behavioral changes observed in adult mice. This work demonstrates that signaling through 5-HT1A receptors during adolescence (a time when pathological anxiety emerges), but not early adulthood, is critical in regulating anxiety setpoints. These data suggest the possibility that brief interventions in the serotonergic system during adolescence could lead to profound and enduring changes in physiology and behavior.

Social vs. environmental stress models of depression from a behavioural and neurochemical approach.

Major depression is a mental disorder often preceded by exposure to chronic stress or stressful life events. Recently, animal models based on social conflict such as chronic social defeat stress (CSDS) are proposed to be more relevant to stress-induced human psychopathology compared to environmental models like the chronic mild stress (CMS). However, while CMS reproduces specifically core depressive symptoms such as anhedonia and helplessness, CSDS studies rely on the analysis of stress-induced social avoidance, addressing different neuropsychiatric disorders. Here, we study comparatively the two models from a behavioural and neurochemical approach and their possible relevance to human depression. Mice (C57BL/6) were exposed to CMS or CSDS for six weeks and ten days. Anhedonia was periodically evaluated. A battery of test applied during the fourth week after the stress procedure included motor activity, memory, anxiety, social interaction and helplessness. Subsequently, we examined glutamate, GABA, 5-HT and dopamine levels in the prefrontal cortex, hippocampus and brainstem. CMS induced a clear depressive-like profile including anhedonia, helplessness and memory impairment. CSDS induced anhedonia, hyperactivity, anxiety and social avoidance, signs also common to anxiety and posttraumatic stress disorders. While both models disrupted the excitatory inhibitory balance in the prefrontal cortex, CMS altered importantly this balance in the brainstem. Moreover, CSDS decreased dopamine in the prefrontal cortex and brainstem. We suggests that while depressive-like behaviours might be associated to altered aminoacid neurotransmission in cortical and brain stem areas, CSDS induced anxiety behaviours might be linked to specific alteration of dopaminergic pathways involved in rewarding processes.

Chronic social defeat stress model: behavioral features, antidepressant action, and interaction with biological risk factors.

RATIONALE: Chronic social defeat stress (CSDS) has been proposed as a model of depression. However, most CSDS studies rely only on the analysis of stress-induced social avoidance. Moreover, the predictive validity of the model has been poorly analyzed, let alone its interaction with biological risk factors. OBJECTIVES: Here, we explore the validity of CSDS as a depression model. Further, the effect of decreased vesicular glutamate transporter 1 (VGLUT1), as a potential factor enhancing a depressive-like phenotype, was studied. METHODS: Mice were exposed to CSDS (10 days) followed by saline, venlafaxine, fluoxetine, or tianeptine treatment (30 days). The battery of behaviors included motor activity, memory, anxiety, social interaction, helplessness, and anhedonic-like behavior. Moreover, the behavioral effect of CSDS in VGLUT1 heterozygous (VGLUT1+/-) mice was studied, as well as the regulation of VGLUT1 mRNA. RESULTS: CSDS induced anhedonia, helplessness, hyperactivity, anxiety, social avoidance, and freezing, as well as downregulation of VGLUT1 mRNA in the amygdala. Repeated venlafaxine showed antidepressant-like activity and both venlafaxine and tianeptine behaved as effective anxiolytics. CSDS-induced social avoidance was reverted by tianeptine. Fluoxetine failed to revert most of the behavioral alterations. VGLUT1+/- mice showed an enhanced vulnerability to stress-induced social avoidance. CONCLUSION: We suggest that CSDS is not a pure model of depression. Indeed, it addresses relevant aspects of anxiety-related disorders. Firstly, CSDS-induced anhedonia and social avoidance are not associated in this model. Moreover, CSDS might be affecting brain areas mainly involved in the processing of social behavior, such as the amygdala, where the glutamatergic mechanism could play a key role.

Chronic stress and impaired glutamate function elicit a depressive-like phenotype and common changes in gene expression in the mouse frontal cortex.

Major depression might originate from both environmental and genetic risk factors. The environmental chronic mild stress (CMS) model mimics some environmental factors contributing to human depression and induces anhedonia and helplessness. Mice heterozygous for the synaptic vesicle protein (SVP) vesicular glutamate transporter 1 (VGLUT1) have been proposed as a genetic model of deficient glutamate function linked to depressive-like behaviour. Here, we aimed to identify, in these two experimental models, gene expression changes in the frontal cortex, common to stress and impaired glutamate function. Both VGLUT1(+/-) and CMS mice showed helpless and anhedonic-like behavior. Microarray studies in VGLUT1(+/-) mice revealed regulation of genes involved in apoptosis, neurogenesis, synaptic transmission, protein metabolic process or learning and memory. In addition, RT-PCR studies confirmed gene expression changes in several glutamate, GABA, dopamine and serotonin neurotransmitter receptors. On the other hand, CMS affected the regulation of 147 transcripts, some of them involved in response to stress and oxidoreductase activity. Interestingly, 52 genes were similarly regulated in both models. Specifically, a dowregulation in genes that promote cell proliferation (Anapc7), cell growth (CsnK1g1), cell survival (Hdac3), and inhibition of apoptosis (Dido1) was observed. Genes linked to cytoskeleton (Hspg2, Invs), psychiatric disorders (Grin1, MapK12) or an antioxidant enzyme (Gpx2) were also downregulated. Moreover, genes that inhibit the MAPK pathways (Dusp14), stimulate oxidative metabolism (Eif4a2) and enhance glutamate transmission (Rab8b) were upregulated. We suggest that these genes could form part of the altered "molecular context" underlying depressive-like behaviour in animal models. The clinical relevance of these findings is discussed.

Leiomioma duodenal gigante: a propósito de un caso / Giant duodenal leiomioma, case report

No disponible