Environmental Fe, Ti, Al, Cu, Hg, Bi, and Si Nanoparticles in the Atrioventricular Conduction Axis and the Associated Ultrastructural Damage in Young Urbanites: Cardiac Arrhythmias Caused by Anthropogenic, Industrial, E-Waste, and Indoor Nanoparticles.

Air pollution exposure is a risk factor for arrhythmia. The atrioventricular (AV) conduction axis is key for the passage of electrical signals to ventricles. We investigated whether environmental nanoparticles (NPs) reach the AV axis and whether they are associated with ultrastructural cell damage. Here, we demonstrate the detection of the shape, size, and composition of NPs by transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometry (EDX) in 10 subjects from Metropolitan Mexico City (MMC) with a mean age of 25.3 ± 5.9 and a 71-year-old subject without cardiac pathology. We found that in every case, Fe, Ti, Al, Hg, Cu, Bi, and/or Si spherical or acicular NPs with a mean size of 36 ± 17 nm were present in the AV axis in situ, freely and as conglomerates, within the mitochondria, sarcomeres, lysosomes, lipofuscin, and/or intercalated disks and gap junctions of Purkinje and transitional cells, telocytes, macrophages, endothelium, and adjacent atrial and ventricular fibers. Erythrocytes were found to transfer NPs to the endothelium. Purkinje fibers with increased lysosomal activity and totally disordered myofilaments and fragmented Z-disks exhibited NP conglomerates in association with gap junctions and intercalated disks. AV conduction axis pathology caused by environmental NPs is a plausible and modifiable risk factor for understanding common arrhythmias and reentrant tachycardia. Anthropogenic, industrial, e-waste, and indoor NPs reach pacemaker regions, thereby increasing potential mechanisms that disrupt the electrical impulse pathways of the heart. The cardiotoxic, oxidative, and abnormal electric performance effects of NPs in pacemaker locations warrant extensive research. Cardiac arrhythmias associated with nanoparticle effects could be preventable.

Tracheal growth assessment in mongrel puppies (dogs) through multidetector CT.

The aim of this study was to describe the tracheal growth pattern and its zoometric relationship in related medium-sized mongrel puppies through adulthood. Fourteen puppies were studied. CT monitoring was performed monthly, starting in the 1st month of life through the 7th month and subsequently at the 9th and 12th months. Additionally, six zoometric measurements were performed. Dorsoventral (DV) and transverse (TV) diameters and the luminal area from C1 to T2 were obtained. The global tracheal growth pattern revealed an increase up to 13 times its initial size, reaching a plateau phase during the last trimester. The relationship between the DV and the TV internal diameters of the tracheal lumen did not change during growth. As previously reported, the cranial tracheal area was wider, while the caudal part gradually decreased towards T1-T2; this consideration is important since the more distal an endotracheal tube is inserted, the greater the risk that injury may occur. The linear correlation between the zoometric measurements and the tracheal ring areas was positive. This study provides evidence for the evaluation of the morphometry of the canine trachea during physiological growth using helicoidal CT as a non-invasive, accurate tool.

Exposures to fine particulate matter (PM2.5) and ozone above USA standards are associated with auditory brainstem dysmorphology and abnormal auditory brainstem evoked potentials in healthy young dogs.

BACKGROUND: Delayed central conduction times in the auditory brainstem have been observed in Mexico City (MC) healthy children exposed to fine particulate matter (PM2.5) and ozone (O3) above the current United States Environmental Protection Agency (US-EPA) standards. MC children have α synuclein brainstem accumulation and medial superior olivary complex (MSO) dysmorphology. The present study used a dog model to investigate the potential effects of air pollution on the function and morphology of the auditory brainstem. METHODOLOGY: Twenty-four dogs living in clean air v MC, average age 37.1 ± 26.3 months, underwent brainstem auditory evoked potential (BAEP) measurements. Eight dogs (4 MC, 4 Controls) were analysed for auditory brainstem morphology and histopathology. RESULTS: MC dogs showed ventral cochlear nuclei hypotrophy and MSO dysmorphology with a significant decrease in cell body size, decreased neuronal packing density with regions in the nucleus devoid of neurons and marked gliosis. MC dogs showed significant delayed BAEP absolute wave I, III and V latencies compared to controls. CONCLUSIONS: MC dogs show auditory nuclei dysmorphology and BAEPs consistent with an alteration of the generator sites of the auditory brainstem response waveform. This study puts forward the usefulness of BAEPs to study auditory brainstem neurodegenerative changes associated with air pollution in dogs. Recognition of the role of non-invasive BAEPs in urban dogs is warranted to elucidate novel neurodegenerative pathways link to air pollution and a promising early diagnostic strategy for Alzheimer's Disease.

[Experimental bacterial contamination of bile and liver in mongrel dogs: an alternative treatment with cephalone, a hybrid of cephalosporine fluoroquinolone]. / Contaminación bacteriana experimental de bilis e hígado en perros criollos. Tratamiento alternativo con (cefalona), un híbrido de cefalosporina y fluoroquinolona.

OBJECTIVES: A longitudinal, randomized, single blind study was done to evaluate the efficacy of an antibacterial hybrid molecule (beta-lactamic-fluoroquinolone) named cephalone after biliary-enteric-bypass (BEB). MATERIAL AND METHODS: Four groups of mongrel dogs were operated on three consecutive periods. Cultures of bile and liver were obtained and assessed, followed by obliteration of common bile duct and BEB to groups A, B and C. Group D served as a control. Ten days later the group A received conventional treatment based on ampicillin/gentamicin and groups B and C, cephalone in two different concentration schemes during 10 consecutive days. Further samples were processed for bacteria and additional liver biopsies were obtained for histopathological analysis. RESULTS: All three treatments reverted bacterial contamination in the liver and most of the bile samples were negative or showed a significant decrease in the number of colony forming units (p = 0.002). Histopathological analysis proved no lesions. CONCLUSIONS: Comparison of efficacy among antibacterial treatments revealed undistinguishable efficacy in this short-term assessment of bacterial contamination after BEB in dogs. The use of cephalone could be considered as a viable treatment or prophylaxis in bacterial infections occurring after BEB. Further studies are needed to assess long-term impact of the cephalone in this setting.

Neuro-protective effects of carbamazepine on sleep patterns and head and body shakes in kainic acid-treated rats.

UNLABELLED: The aim of this work was to analyze the effect of carbamazepine (CBZ) on sleep patterns and on "head and body shakes" and to determine the role of serotonin (5-HT) in a model of kainic-induced seizures. Thirty male Wistar rats (280-300 g) were used for polygraphic sleep recording. After a basal recording, the rats were allocated into three groups: kainic acid-treated animals (KA; 10 mg/kg; n=10), carbamazepine-treated animals (CBZ; 30 mg/kg; n=10) and animals injected with KA 30 min after pretreatment with CBZ (CBZ+KA; n=10). Polygraphic recordings were performed for 10 h for 3 days, with the exception of the CBZ group, which were observed for 1 day. In order to measure the head and body shakes that occurred over that time, a behavioral assessment was performed in two additional groups of KA (n=10) and CBZ+KA (n=10) animals. After 10 h of behavioral assessment, the rats were sacrificed, and the levels of 5-HT and 5-hydroxy-indol-acetic acid (5-HIAA) were analyzed. We compared these findings with the results from a group of rats without pharmacological intervention (n=10). All of the recordings were performed from 08:00 to 18:00 h. DATA ANALYSIS: the electrographic parameters, head and body shake counting and monoamine concentrations were analyzed by an ANOVA test. Differences of *p < or = 0.01 and **p < or = 0.001 were considered statistically significant. Our results showed that CBZ exerted a protective effect on sleep pattern alterations induced by KA, which when administered alone caused a complete inhibition of sleep for the first 10 h after administration. Although there was a reduction in the amount of sleep after the administration of KA in CBZ-pretreated animals, sleep inhibition was incomplete. In addition, CBZ decreased the frequency of head and body shakes by 60% as compared to KA. The 5-HT and 5-HIAA levels in the pons were increased in the KA and KA+CBZ groups. Our conclusion is that in addition to decreasing seizure intensity, CBZ facilitates the partial recovery of sleep. These results suggest that CBZ provides neuro-protective effects on sleep and against seizures.

Difusión de cotrimoxazol a través de un expansor tisular: Estudio in vitro / Cotrimoxazole diffusion through a tissue expanders: In vitro study

Introducción: La principal complicación del uso de los expansores titulares (ET) son las infecciones. Una alternativa para evitarla, es agregar antibióticos que se difundan a través de la pared de un ET y eviten la colonización bacteriana. El objetivo de este trabajo fue evaluar la eficacia de una presentación nacional de cotrimoxazol, para difundirse a través de un ET en diferentes volúmenes de expansión. Material y método: Se realizó un experimento longitudinal con 12 ET, llenados a 50,100, 150 o 200% de su capacidad nominal, con solución fisiológica y cotrimoxazol a una concentración de 800/4000 ug/mL de trimetoprin/sulfametoxazol (TMX/SMX), sumergidos posteriormente en un sistema cerrado. Se midió la presión en el interior del ET, al inicio y al final del experimento. En los cuatro grupos se cuantificó la concentración de cotrimoxazol en la solución del contenedor, durante nueve días consecutivos. Los resultados se compararon mediante ANOVA de dos vías. Resultados: El SMX se precipitó dentro del ET. Las concentraciones de TMX en la solución del contenedor fueron diferentes en función del tiempo y el porcentaje de expansión. No hubo correlación entre el porcentaje de expansión y la presión dentro del ET. Conclusiones: La sinergia de cotrimoxazol de uso endovenoso disponible en nuestro país, no es una buena opción a emplearse en un ET a las dosis utilizadas, ya que el coeficiente de solubilidad de SMX se saturó y se formaron cristales. El incremento de difusión de TMX estuvo asociado con un mayor porcentaje de expansión, lo que es una ventaja, considerando que las infecciones son más frecuentes al final del proceso de expansión.

Introduction: Infection associated with tissue expansion is one of the main complications and force to take away the tissue expander. An alternative to avoid this action is to dilute antibiotics inside it. The aim of this experiment was to quantify the concentration of cotrimoxazole diffused through a tissue expander at different expansion and pressure volumes. Material and methods: A test was performed with 12 tissue expanders immersed in a closed system. These were divided in 4 sets according to the introduced expansion rate. Three independent variables were considered: percentage of lumen volume introduced into the expander, pressure inside the expander, and experiment duration. The concentration of the drug diffused through the expander was taken as dependent variable. The solution in which the expander was immersed was continuously sampled and drug concentration was determined by High Performance Liquid Chromatography (HPLC). ANOVA was used to determine differences between concentrations measured of every variable applied. Results: Only trimethoprim (TMX) diffused. No lineal correlation was observed between expansion rate and pressure inside the expander. The difference with respect to time and concentration of the drug outside the expander was statistically significant among the 4 sets of expanders (p = 0.0000). Conclusion: Sulfametoxazole (SMX) did not diffuse and crystallized inside the expander because of the different pk of the two drugs (SMX-TMX) respect to pH of dilution which was similar to pK of trimethoprim. The expansion rate had a proportional effect on TMX concentration outside the expander: an over-expansion of the system greater than 200% increases diffusion highly.