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Ventilatory sensitivity to ammonia occurs in teleosts, elasmobranchs and mammals. Here, we investigated whether the response is also present in hagfish. Ventilatory parameters (nostril flow, pressure amplitude, velar frequency and ventilatory index, the last representing the product of pressure amplitude and frequency), together with blood and water chemistry, were measured in hagfish exposed to either high environmental ammonia (HEA) in the external sea water or internal ammonia loading by intra-vascular injection. HEA exposure (10â mmolâ l-1 NH4HCO3 or 10â mmolâ l-1 NH4Cl) caused a persistent hyperventilation by 3â h, but further detailed analysis of the NH4HCO3 response showed that initially (within 5â min) there was a marked decrease in ventilation (80% reduction in ventilatory index and nostril flow), followed by a later 3-fold increase, by which time plasma total ammonia concentration had increased 11-fold. Thus, hyperventilation in HEA appeared to be an indirect response to internal ammonia elevation, rather than a direct response to external ammonia. HEA-mediated increases in oxygen consumption also occurred. Responses to NH4HCO3 were greater than those to NH4Cl, reflecting greater increases over time in water pH and PNH3 in the former. Hagfish also exhibited hyperventilation in response to direct injection of isotonic NH4HCO3 or NH4Cl solutions into the caudal sinus. In all cases where hyperventilation occurred, plasma total ammonia and PNH3 levels increased significantly, while blood acid-base status remained unchanged, indicating specific responses to internal ammonia elevation. The sensitivity of breathing to ammonia arose very early in vertebrate evolution.
Asunto(s)
Amoníaco/metabolismo , Anguila Babosa/fisiología , Respiración , Agua de Mar/química , AnimalesRESUMEN
INTRODUCTION: Valproic acid (VPA)-induced hyperammonemia poses several clinical challenges in psychiatric medicine. The reported incidence of this adverse effect varies widely across the literature. Furthermore, practitioners treat hyperammonemia in asymptomatic patients although studies suggest this practice is unnecessary. The purpose of this study is to evaluate if patients with VPA-induced hyperammonemia are appropriately identified for treatment based on their symptom presentation as well as determine the most efficacious treatment approach for VPA-induced hyperammonemia. METHODS: This study was completed at a community teaching hospital, and patients were retrospectively identified from June 1, 2011, to June 30, 2016, and included if they were admitted to a psychiatric unit, received at least 1 dose of VPA, and had at least 1 ammonia level drawn during admission. Hyperammonemia was defined as greater than 47 µmol/L, and symptomatic hyperammonemia was defined based on specific symptom presentation. The treatment modality was successful if the ammonia level was within normal range at discharge. RESULTS: Of the 357 patients screened, 347 patients met all inclusion criteria for analysis. The reported incidence of hyperammonemia was found to be 36% with 43.2% of those patients presenting with symptoms. Lactulose initiation was the most common treatment modality chosen (48.7%). Discontinuation of VPA was the most effective treatment (56.3% success rate). DISCUSSION: The results demonstrate that many patients with elevated ammonia levels are asymptomatic and therefore, based on findings within the literature, may not require treatment. Although lactulose was found to be the most common treatment initiated, the most effective was discontinuation of VPA.
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Ammonia levels were evaluated in the urban environment of Madrid City, Spain. A total of 110 samplers were distributed throughout the city. Vehicle traffic density, garbage containers and sewers were identified as local emission sources of ammonia. The average ammonia concentrations were 4.66 ± 2.14 µg/m3 (0.39-11.23 µg/m3 range) in the winter and 5.30 ± 1.81 µg/m3 (2.33-11.08 µg/m3 range) in the summer. Spatial and seasonal variations of ammonia levels were evaluated. Hotspots were located in the south and center of Madrid City in both winter and summer seasons, with lower ammonia concentrations located in the north (winter) and in the west and east (summer). The number of representative points that were needed to establish a reliable air quality monitoring network for ammonia was determined using a combined clustering and kriging approach. The results indicated that 40 samplers were sufficient to provide a reliable estimate for Madrid City.
Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire , Amoníaco/análisis , Monitoreo del Ambiente/métodos , Ciudades , Estaciones del Año , EspañaRESUMEN
The aim of this paper is to evaluate the relationship of salivary ammonium levels and the presence of bacteria with rheumatoid arthritis (RA) clinical disease activity in a cross-sectional study of Mexican patients. From a periodontal and disease activity standpoint, 132 consecutive RA patients fulfilling clinical criteria were evaluated. Ammonia levels (including peptidyl arginine deiminase activity) were evaluated by colorimetric assay and the presence of Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia was evaluated by polymerase chain reaction (PCR) technique. After a multivariate analysis, adjusting for clinical and serological parameters, a significant association was only observed between severe periodontitis and probing depth with high RA disease activity. Additionally, in contrast to P. gingivalis, the presence of T. forsythia was significantly associated with high disease RA activity even after multivariable adjustment analysis. There was also a significant increase in ammonium levels in the high RA activity group and a significant correlation between salivary ammonia and RA disease activity but not with autoantibody titers. Similarly, we observed a significant increase in the ammonium levels derived from the cultures of P. gingivalis and T. forsythia, with respect to P. intermedia and S. gordonii cultures, or even healthy donors. These results suggest that RA activity is associated with severe periodontitis, high salivary ammonium levels and the presence of T. forsythia.
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We report the case of an aborted awake craniotomy for a left frontotemporoinsular glioma due to ammonia encephalopathy on a patient taking Levetiracetam, valproic acid and clobazam. This awake mapping surgery was scheduled as a second-stage procedure following partial resection eight days earlier under general anesthesia. We planned to perform the surgery with local anesthesia and sedation with remifentanil and propofol. After removal of the bone flap all sedation was stopped and we noticed slow mentation and excessive drowsiness prompting us to stop and control the airway and proceed with general anesthesia. There were no post-operative complications but the patient continued to exhibit bradypsychia and hand tremor. His ammonia level was found to be elevated and was treated with an infusion of l-carnitine after discontinuation of the valproic acid with vast improvement. Ammonia encephalopathy should be considered in patients treated with valproic acid and mental status changes who require an awake craniotomy with patient collaboration.