Disease relevance of dichloro-difluoro-methane

• Difluorodichloromethane (FC12) inhaled at high concentrations sensitises, as do numerous other volatile organic compounds, mammalian heart to adrenaline induced arrhythmias [1].
• Inhalation of 10 or 20% fluorocarbon 12 produced a decline in cardiac output and a dose-related depression of peak left ventricular (LV) dP/dt without associated arrthythmias, hypoxemia or significant changes in LV end-diastolicpressue or heart rate [2].
• Use of Freon 12 in treating verruca lesions [3].
• Contact allergic dermatitis caused by freon 12 in deodorants [4].
• Allergic contact dermatitis from ethyl chloride and sensitization to dichlorodifluoromethane (CFC 12) [5].

High impact information on dichloro-difluoro-methane

• Cardiovascular effects of acute and chronic inhalations of fluorocarbon 12 in rabbits [2].
• Breathing fluorocarbon 12 for 30 minutes caused a decline in peak LV dP/dt, cardiac output, LV systolic pressure and mean arterial pressure which was present throughout the exposure period [2].
• Standards development of global warming gas species: methane, nitrous oxide, trichlorofluoromethane, and dichlorodifluoromethane [6].
• The emissions of CFC-12 and HFC-134a were mainly attributed to the losses from A/C-systems of passenger cars, whereas the emissions of HCFC-22 originate from losses of refrigeration systems of transport trucks [7].
• 1,1,1,2-Tetrafluoroethane (R-134a) is a non-ozone-depleting alternative to dichlorodifluoromethane for use as an air-conditioning refrigerant and as a propellant in anti-asthmatic and other pharmaceutical preparations [8].

Biological context of dichloro-difluoro-methane

• Estimates of the greenhouse warming potential (GWP) relative to CFC-12 yield values of 0.02-0.14, resulting in a relative contribution to global warming of all volatile anaesthetics of approximately 0.03% [9].
• Fluorocarbon aerosol propellants XI: Pharmacokinetics of dichlorodifluoromethane in dogs following single and multiple dosing [10].
• The doses of four gaseous general anaesthetic agents required to reduce electrically evoked action potentials by 50% (mean +/- SEM) were nitrous oxide 490 +/- 40.4 kPa, ethylene 665 +/- 212 kPa, dichlorodifluoromethane 108 +/- 17.2 kPa and cyclopropane 70 +/- 5 kPa [11].
• Donkeys were exposed to trichlorofluoromethane (FC11), dichlorodifluoromethane (FC12) and an equivolume mixture of the two to determine their effects on tracheobronchial particle deposition and mucociliary clearance [12].

Anatomical context of dichloro-difluoro-methane

• HeLa cells were frozen in melting Freon-12 ( CCl2F2 ), dried under vacuum at -30 degrees C, sonicated in hexylene glycol at -35 degrees C, and centrifuged through either propylene glycol or a mixture of the two glycols at -40 degrees C. The centrifugation yielded a nuclear pellet and a cytoplasmic supernatant [13].
• The temperature of a mandibular incisor pulp chamber was measured in degree C 10 s after the application of the dichlorodifluoromethane (DDM) to the midfacial surface of the crown [14].

Associations of dichloro-difluoro-methane with other chemical compounds

• Subsequent re-exposure to the spray and patch tests revealed contact sensitization to ethyl chloride and dichlorodifluoromethane (CFC 12) [5].
• Long-term carcinogenicity bioassays on three chlorofluorocarbons (trichlorofluoromethane, FC11; dichlorodifluoromethane, FC12; chlorodifluoromethane, FC22) administered by inhalation to Sprague-Dawley rats and Swiss mice [15].
• Half-life of the fluorocarbons in the arterial blood after one puff of metered aerosol was 69 to 80 sec for fluorocarbon 11 and 57 to 67 sec for fluorocarbon 12 [16].
• The inhalation of trichlorofluoromethane (FC11), dichlorotetrafluoroethane (FC114) and dichlorodifluoromethane (FC12) caused a reduction in mean aortic blood pressure but only FC11 and FC114 caused a reduction in mean pulmonary arterial pressure [17].

Analytical, diagnostic and therapeutic context of dichloro-difluoro-methane

• Small pieces of tissue, and cell suspensions in plastic artificial insemination (AI) 'straws', were frozen rapidly in Freon-12 at -155 degrees C, without pre-treatment [18].
• It can be treated with cryosurgery using Refrigerant 12 with successful clinical and aesthetic results [19].

References