Search

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.

Background Delayed central conduction times in the auditory brainstem have been observed in Mexico City (MC) healthy children exposed to fine particulate matter (PM 2.5 ) and ozone (O 3 ) 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.

Portacaval shunts are commonly used to prevent gastroesophageal variceal bleeding secondary to portal hypertension. Ammonia encephalopathy is a common complication and it’s management includes antibiotics such as metronidazole, neomycin and recently, rifaximin. Metronidazole is often used in this context but its pharm acokinetics may be altered in these patients. Compare the pharmacokinetic parameters of two groups of rats, one of them after one year of having undergone mesocaval shunt. A randomized, experimental, prospective study in twenty adult male Lewis rats divided into two groups. The first group underwent mesocaval shunt and the other was the control group. Analyses of the following parameters were performed in both groups: (1) Pharmacokinetics of metronidazole by high-performance liquid chromatography, (2) Transaminase levels and (3) Body and liver weight. Differences between the MCS group and the control group were found for the pharmacokinetic parameters: Cm ax (p = 0.004), Ka (p = 0.009), Ka tl/2 (p = 0.007), Vd (p = 0.01), AUC (p = 0.05) and tmax (p = 0.01) and in ALT levels (p = 0.03) and liver weight (p = 0.00). The results obtained in this experimental model during one year of mesocaval shunt led us to suggest that metronidazole dosage should be decreased, without altering the administration schedule, because the drug levels reached in the mesocaval shunt group caused the animals to behave as if they had been given higher doses. © 2015 Asian Network for Scientific Information.

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.

This study evaluated a polylactic and polyglycolic acid (PLA/PGA) implant as a partial tracheal substitute in young developing canines. This experimental and longitudinal study included local stray pups that received substitution of a short cervical tracheal segment with a PLA 85%/PGA 15% plaque. We measured clinical, endoscopic, and tomographic variables for 1 year, at which time we performed histomorphological evaluations of the implant using light and electron microscopy. There were no adverse events throughout the clinical progression. On endoscopic evaluation, the implant was covered with mucosal tissue beginning in the first month, without granulation or stenosis, and the circular shape of the trachea was altered. Tomographic images of the tracheal area at the implant site were similar to adjacent healthy areas (p = 0.423). At the end of the follow-up period, the plaque had biodegraded, and the space was covered by pseudostratified epithelium and ciliated cells similar to the neighboring tissue. Implantation of a PLA/PGA plaque constituted an effective (functional) replacement of a short semicircular cervical tracheal segment without limiting the growth of the recipient. Additional studies are required to prove the efficacy of these implants for larger tracheal segment replacements and in subjects at different stages of development.

Background:Collagen-covered prostheses can be used as a non-circumferential segmental tracheal replacement. However, the applicability of these implants in young subjects has not yet been reported.Methods:In this experimental, longitudinal study, dogs aged 29–32 days underwent limited segmental tracheal replacement with a polyester prosthesis or were allocated to a control, untreated group. The dogs were evaluated clinically, endoscopically and tomographically for up to one year.Results:Although there was evidence of tracheal growth in the experimental group, tomographic measurements were significantly smaller in this group than in the control group throughout the observation period. At the end of the study, there was no evidence of implant rejection, stenosis or collapse. Normal respiratory epithelium had grown across the implanted membrane in the experimental group.Conclusion:The homologous collagen mersylene membrane allowed for limited structural tracheal growth and was functionally integrated into the segmented tracheal wall in growing dogs.

As part of the development of a new series of antibacterial agents derived from coupling a beta-lactamic precursor with a fluoroquinolone and named cephalones, the pharmacokinetics of one derivate: CQ-M-EPCA in rats after intravenous, intragastric and intraduodenal routes, was carried out. After the IV injection of 20 mg/kg or 40 mg/kg of this cephalone, plasma concentrations at the time zero (Cp0) were 3.1 and 11.26 microg/ml, respectively. Plasma concentrations decreased rapidly to almost disappear in both instances. Forty-five minutes later, a surge in concentrations, in the 40 mg/kg group, with a maximal plasma concentration (Cpmax) of 2.97 microg/ml was observed. An elimination half-life (T1/2el) of 2.36 +/- 0.33 h. was calculated. The drug was undetected by the ninth hour. Intragastric administration of the drug resulted in Cpmax of 3.78 +/- 0.26 microg/ml with a time to reach Cpmax (Tmax) of 25 min and T1/2el = 3.22 h. Same variables after intraduodenal administration were Cpmax 4.71 microg/ml; Tmax 1h, and T1/2el 3.41 h. Outstandingly high bioavailabilities after intragastric and intraduodenal administration (169 and 246%, respectively), together with the shape of the concentration versus time profiles after IV administration suggest that the drug undergoes a complex redistribution phenomenon, while showing high tissue diffusion with an apparent volume of distribution of 3.33 l/kg.

This study evaluated the effects of thiamine pyrophosphate (PPT) on the biochemical profiles of full-term rabbit foetuses that were subjected to experimental ischemia followed by 24 h reperfusion. A total of 16 gestating rabbit dams were divided into two groups, one of which was treated by administering PPT and subjected to a process ischemia. During this interval, fetal blood samples were drawn from each dam (in the ischemia group) at 0, 15 and 45 min. Ischemia for 15 and 45 min was not associated with changes in lactate levels of the Ischemia group foetuses. However, in the foetuses in the reperfusion groups without PPT lactate levels were significantly higher after 15 and 45 min of arterial occlusion compared to time zero. These results demonstrate that PTT alters some acute and some longer-term biochemical outcomes of uterine ischemia perhaps important in preserving energy metabolism under hypoxic conditions.

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 ≤ 0.01 and **p ≤ 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.

Plication of a nonfunctional hemidiaphragm usually restores altered ventilatory mechanics. This study compared two techniques in performing diaphragmatic plication: video-assisted thoracoscopy (group A) and thoracotomy (group B).Twenty dogs with induced paralysis of the right hemidiaphragm were randomly assigned to one of the two groups. Evaluations were performed before and after plication of the respiratory frequency (f) and lung area (LA) of the affected side. Operative time, time to resumption of walking, ingestion of fluids and solid food, pain intensity, and postoperative complications were measured.Group A had less pain after the surgery (P0.0001), earlier fluid ingestion (P0.05), and earlier resumption of walking (P0.019). Four weeks after the procedure, LA was similar in both groups, while a significant decrease in f was recorded in group A (P0.02). The remaining evaluated variables showed no differences.Both approaches were effective. Pain recorded in the postoperative period was less and recovery was faster in group A. Complications and surgical times were similar. The video-assisted thoracoscopy is a safe and efficient option for performing diaphragmatic plication in dogs.

Bacterial contamination after hepatic- biliary-enteric bypass (HBEB) in children with biliary atresia requires an effective treatment. Involved bacteria often develops antimicrobial resistance to conventional antibiotics. A longitudinal, randomized, single blind study was done to evaluate a new antibacterial hybrid molecule (β-lactamic-fluoroquinolone) named cephalon after HBEB. Four groups of mongrel dogs were operated on three consecutive periods. During the first intervention cultures of bile and liver were obtained and assessed, followed by obliteration of common bile duct and HBEB to groups A, B and C. Group D was the control group. Ten days later new samples were repeated. Once identified the presence of microorganisms in bile samples and in more than an half of liver cultures, group A received conventional treatment based on ampicillin/gentamicin and groups B and C, received the cephalon in two different doses during 10 days in all cases. Further samples were processed for bacteria and additional liver biopsies were obtained for histopathological analysis. All three treatments reverted bacterial contamination in the liver; more than half of the bile samples were negative or showed a significant decrease in the number of colony forming units ( p = 0.002). None histopathological lesions were proved. Comparison of efficacy among antibacterial treatments revealed undistinguishable efficacy in this short-term assessment of bacterial contamination after HBEB in mongrel dogs. The use of cephalon could be considered as a viable prophylaxis and treatment in bacterial infections occurring in HBEB patients. Additional studies are needed to assess long-term impact of the cephalon in this setting.

Objective Fibrocollagen-covered polyester meshes can be used as possible substitutions for tracheal segments if they become integrated into the tissue without complications. The aim of this study was to assess a fibrocollagen-covered polyester prosthesis to be used as a substitution for a tracheal segment. Methods We performed a blind, randomized experimental assay. Adult Wistar rats were assigned to one of 2 groups. Prostheses were made by implanting polyester tubing in a group of animals to cover them with homologous collagen. They were implanted as substitutions of tracheal segments in the experimental group after creating a defect in the anterior wall of the trachea. Clinical, histomorphologic, and immunohistochemical assessments were made at 4 different time points. Results The experimental group presented some respiratory distress signs during the first 7 to 10 days, such as stertors, hissing, and low motor activity. After this initial period, the symptoms subsided progressively and disappeared at the end of the first month. These respiratory symptoms caused no mortality. Initially undifferentiated monolayer cells predominated on the implant's surface, but during the last 2 months, the proportion of epithelial and ciliated cells was similar to that seen in control animals. Types I, III, and V collagen fibers were identified around the mesh. The intraluminal area of the tracheas with prostheses and prosthesis thickness were larger during the 4 months of the experiment. The increase in thickness was due to angiogenesis without evidence of fibrosis or chronic inflammation. Conclusions Polyester-collagen prostheses used as substitutions of tracheal segments in rats enabled the proliferation of normal respiratory epithelium and maintained tracheal function without collapse, inflammatory reaction, or secondary stenosis.