silicon and hexafluorosilicic-acid

We studied ouabain-sensitive Na-K adenosine triphosphatase (ATPase) activities in the iris-ciliary body of rabbit eyes after lensectomy-vitrectomy. Changes in enzyme activities were quantitatively investigated in the plasma membrane of iris-ciliary body at 0 or 7 hours and at days 1, 3, 7, and 14. The specific activity of Na-K ATPase rose to significantly higher levels than the control value at 7 hours following surgery, but returned to the baseline value after 7 days. In addition, we evaluated enzyme activities after lensectomy-vitrectomy during which SF6 or silicone oil was injected. The specific activity of Na-K ATPase following the injection of SF6 or silicone oil was significantly higher than the control value at 7 hours and did not return to the normal value even after 14 days. Consensual reaction, demonstrated by increased Na-K ATPase activity, also was found in the contralateral unoperated eyes of SF6- and silicone oil-injected rabbits. The increased Na-K ATPase activity in the iris-ciliary body after experimental surgery may play an important role in restoring swollen tissues.

Topics: Animals; Cell Membrane; Ciliary Body; Fluorides; Iris; Lens, Crystalline; Ouabain; Rabbits; Silicic Acid; Silicon; Silicone Oils; Sodium-Potassium-Exchanging ATPase; Vitrectomy

Topics: Administration, Inhalation; Administration, Oral; Animals; Dose-Response Relationship, Drug; Female; Fluorides; Guinea Pigs; Liver; Male; Maximum Allowable Concentration; Nervous System; Rabbits; Rats; Silicic Acid; Silicon

For 12 hours, excess hydrofluorosilicic acid was diverted to a 127-home community water supply. Fluoride levels peaked at 51 parts per million (ppm). Water acidification caused copper to leach from the domestic plumbing; raising copper levels to 25-41 ppm. Fifty-two (33 per cent) of those who drank hyperfluoridated water developed mild gastroenteritis. Vomiting was uncommon and symptom onsets usually occurred greater than 30 minutes after drinking water; suggesting that fluoride, rather than copper, caused illness. Skin contact with hyperfluoridated water caused itching and skin rashes.

Topics: Accidents, Occupational; Connecticut; Fluoridation; Fluorides; Gastroenteritis; Humans; Silicic Acid; Silicon; Skin Diseases; Water Pollution, Chemical; Water Supply

Hypoxic pulmonary vasoconstrictor (HPV) responses were measured with repeated intermittent hypoxic challenges in eight non-traumatized closed chest dogs anesthetized with pentobarbital. The right lung was ventilated continuously with 100% O2 while the left lung was either ventilated with 100% O2 (control) or ventilated with a gas mixture containing 3-4% O2 (hypoxia). Mean per cent left lung blood flow for all four normoxic periods was 43.1 +/- 1.5% (mean +/- SE) of the total blood flow by the SF6 excretion method and 40.8 +/- 1.1% by the differential CO2 excretion method, corrected for the Haldane effect. With hypoxic ventilation, flow diversion from the hypoxic lung was maximal with the first exposure and did not change subsequently with a total of four alternating exposures to normoxia and hypoxia. Flow diversion during hypoxia was approximately 50.5 +/- 2.4% by the SF6 method and 50.3 +/- 3.5% by the VCO2 method. This result contrasts with the increasing flow diversion response with intermittant hypoxic exposure that has been reported in animals exposed first to thoracotomy and surgical dissection. It is concluded that in the absence of surgical trauma the initial response to hypoxia is maximal and is not potentiated by repeated hypoxic stimulation.

Topics: Anesthesia, Intravenous; Animals; Dogs; Female; Fluorides; Hypoxia; Pulmonary Circulation; Respiration, Artificial; Silicic Acid; Silicon; Time Factors; Vasoconstriction

Topics: Ammonium Compounds; Fluorides; Food Contamination; Food Handling; Foodborne Diseases; Humans; Quaternary Ammonium Compounds; Silicic Acid; Silicon

Topics: Canada; Fluoridation; Fluorides; Silicic Acid; Silicon

Morphological changes in the skin of animals were studied after application of concentrated hydrofluoric and hexafluorosilicic acid. The intact skin was not generally affected by these acids. Areas injured before application of the acid showed, however, a continuous spreading of necrosis in the deeper regions. The first histological changes were noticed 1 h after the application. Such early histological findings could be seen long before any macroscopic reaction. The main characteristic findings were the hypocellular necrosis and edema reaching as far as the subcutis. The necrosis showed sharp leukocyte demarcations.

Topics: Animals; Epidermis; Fluorides; Forensic Medicine; Guinea Pigs; Hydrofluoric Acid; Necrosis; Rats; Rats, Inbred Lew; Silicic Acid; Silicon; Skin; Swine