It has been shown that chronic repetitive ambient hypoxia, simulating pulmonary gas disturbances observed in apnoea, leads to systemic hypertension in rats. However, the relative roles of hypoxia (HO), hypercapnia (HC), gas stress and vigilance on the cardiovascular changes have not yet been demonstrated. The aim of this study was to investigate the acute haemodynamic changes observed during the repetitive inhalation of various gas mixtures in rats for HO alone and HO+HC, and to analyse the effects of vigilance and of the stress of gas administration. We studied 6 unanaesthetized Wistar rats chronically instrumented with an aortic catheter. Nitrogen, nitrogen+CO2 mixtures and compressed air were randomly administered in a Plexiglass chamber for 10 s and then flushed by compressed air for 20 s. Two cycles were repeated every min for 10 to 12 min. The inhaled gas fractions (FI,O2,FI,CO2) were monitored by O2 and CO2 analysers. Blood pressure (BP) was measured by a P23XL transducer. The blood gases were analysed by a 1306 IL meter. In control experiments, with compressed air alone, there were no significant acute changes in heart rate (HR) and BP. During HO there were no changes in HR or BP at FI,O2 values from 0.05-0.14, whilst at FI,O2 values from 0-0.05 systolic blood pressure (SBP) rose significantly (+25.3 +/- 25.7 (SD) mmHg) and HR decreased (-93.8 +/- 124.1 bpm). During HOHC, SBP rose (+35.1 +/- 26.4 mmHg) and HR decreased (-139.3 +/- 75.7 bpm), significantly more than in HO alone. SBP was linearly correlated with Pa,O2 during HO (r = 0.53) and also during HOHC (r = 0.44) and was not directly related to Pa,CO2 which has, nevertheless, an additive effect to HO. SBP rose with each challenge significantly more when the rats were awake than when asleep (behavioural sleep). We conclude that in this acute repetitive inhalation model, the rise in SBP is not related to gas stress or to Pa,CO2 but to a decrease in Pa,O2 and is enhanced by wakefulness.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1183/09031936.95.08101675 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Design and Process Considerations for Preparation of Modified Release Ivermectin and Praziquantel Tablets by Wet Granulation.
AAPS PharmSciTech
January 2025
University of Maryland, School of Pharmacy, Department of Pharmaceutical Sciences, 20 N Pine Street, Baltimore, Maryland, 21201, USA.
Dosage forms containing Ivermectin (IVER) and Praziquantel (PRAZ) are important combination drug products in animal health. Understanding the relationship between products with differing in vitro release characteristics and bioequivalence could facilitate generics. The goal of this study was to create granulations for each active ingredient, with similar release mechanisms, but substantially different in vitro release rates, and then compressing these granulations into tablets with differing release rates.
View Article and Find Full Text PDFCarbon capture from controlled degassing of deep meromictic lakes: Insights to techno-economic and environmental feasibility, from the "killer lakes" in Cameroon.
Sci Total Environ
January 2025
The University of Yaoundé I, National Advanced School of Engineering of Yaoundé, P.O. Box: 8390, Yaoundé, Cameroon. Electronic address:
Carbon dioxide (CO) accumulation and emission are well-known features of deep lakes, making them a significant unavoidable carbon source to the atmosphere. In the case of meromictic lakes, degassing devices are installed to controllably release through a pipe the CO trapped in the bottom waters. Otherwise, the gas is emitted diffusely at the air-water surface or accidentally through a limnic eruption when the saturation limit is reached.
View Article and Find Full Text PDFHygrometry behavior during high-flow nasal oxygen therapy and non-invasive mechanical ventilation: A narrative review of bench to clinical studies.
J Intensive Med
October 2024
Intensive Care Unit, Hospital Morales Meseguer, Murcia, Spain.
Recently, there has been growing interest in knowing the best hygrometry level during high-flow nasal oxygen and non-invasive ventilation (NIV) and its potential influence on the outcome. Various studies have shown that breathing cold and dry air results in excessive water loss by nasal mucosa, reduced mucociliary clearance, increased airway resistance, reduced epithelial cell function, increased inflammation, sloughing of tracheal epithelium, and submucosal inflammation. With the Coronavirus Disease 2019 pandemic, using high-flow nasal oxygen with a heated humidifier has become an emerging form of non-invasive support among clinicians.
View Article and Find Full Text PDFA Novel Self-Opening Transfer Shuttle for the Transfer of Air-Sensitive Sample to Scanning Electron Microscopy.
Microsc Microanal
January 2025
Instrumental Analysis Center, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian, Liaoning Province 116024, China.
A self-opening transfer shuttle has been designed and fabricated for the transfer of air-sensitive samples to scanning electron microscopy (SEM). Delayed push out of an airtight sample cabin sealed inside the shuttle allows the protection of the sample from air exposure during the pumping of SEM chamber. A compressed spring is employed to automatically drive the push out of the cabin.
View Article and Find Full Text PDFAdvanced adiabatic compressed air energy storage systems dynamic modelling: Impact of the heat storage device.
Heliyon
January 2025
IFP Energies nouvelles, 1 et 4 avenue de Bois Préau, 92852, Rueil-Malmaison, France.
Advanced Adiabatic Compressed Air Energy Storage (AACAES) is a technology for storing energy in thermomechanical form. This technology involves several equipment such as compressors, turbines, heat storage capacities, air coolers, caverns, etc. During charging or discharging, the heat storage and especially the cavern will induce transient behavior of operating points, notably temperature, pressure, and volume flow.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!