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Biomedical subjects

R S Braman

Publications and source records attributed to R S Braman.

10 recordsLinked to original sources
PubMed1995

Method of delivering constant nitric oxide concentrations during full and partial ventilatory support.

OBJECTIVE: The objective of our study was to evaluate the precision and safety of administering nitric oxide (NO) during full and partial ventilatory support. METHODS: NO was administered either using a microprocessor-controlled servo ventilator, substituting an NO-N2 mixture for the ventilator's usual air supply or by adding an NO-N2 mixture with a constant flow at the proximal end of the tracheal tube. NO, nitrogen dioxide (NO2), and nitrous and nitric acid (HNOx) was quantified selectively with a sequential, selective, hollow tube preconcentration and chemiluminescence analysis in a respiratory system model during various modes of full and partial ventilatory support. RESULTS: The servo valve system of the ventilator provided accurate NO concentrations during full and partial ventilatory support. Interaction of spontaneous and mechanical ventilation during partial ventilatory support resulted in irregular inspiratory flow patterns and a difference of 3.6% to 44.1% between the desired and measured inspiratory NO concentrations when NO was administered at a constant flow to the proximal end of the tracheal tube. NO2 was not detected. Small amounts of 0.6 to 0.8 ppm HNOx were detected when 80 ppm NO was administered in a humid gas mixture of 37 degrees C in the presence of 90% oxygen. CONCLUSIONS: NO can be administered accurately without formation of NO2 during full and partial ventilatory support with the electronically controlled valve system of the ventilator. Formation of HNOx is a potential problem at high NO and O2 concentrations in the presence of moisture.

Administration, Inhalation↗
PubMed1989

Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium (III) reduction with chemiluminescence detection.

Nitrite in environmental water samples is reduced at room temperature to nitric oxide in acidic medium containing vanadium (III). Nitrate is also rapidly reduced after heating to 80-90 degrees C. Nitric oxide is removed from the reaction solution by scrubbing with helium carrier gas and is detected by means of a chemiluminescence NOx analyzer. Nanogram detection limits are obtained. The method has the advantage of not requiring highly acidic solutions for nitrate reduction and has been applied to the analysis of a variety of environmental waters, sediment, plant materials, and human urine and blood serum.

Body Fluids↗
PubMed1979

Skin cancer and arsenical intoxication from well water.

A case of acute arsenical intoxication arising from ingested well water containing only 1.2 ppm of arsenic is reported. After a latent period of 14 years, multiple cutaneous basal cell carcinomas developed. The water was analyzed for a variety of other trace elements and compounds and no evidence for the existence of other carcinogens was found. This study strengthens the concept that arsenic is a carcinogen. The role of a possible selenium deficiency is also discussed.

Adult↗
PubMed1977

Applications of arsine evolution methods to environmental analyses.

Because of its biological activity, arsenic is involved in an active global geochemical cycle. Arsenic has been found to be transferred to the atmosphere, at least in part, by evolution of trimethyl arsine and similar methyl arsenic compounds. Because of the environmental importance of the several arsenic forms [inorganic arsenic (III) and (V), methylarsonic acid, dimethylarsenic acid, trimethylarsine, methylarsine, and dimethylarsine], chemical methods for their analysis are needed. Sensitive methods are required because environmental concentrations encountered are generally in the range of 0.01 (or lower) to 3 ppb for natural waters and 1-6 ng As/m3 for arsenic in air. Arsine evolution by pH selective reduction permits specific analyses for inorganic As (III) and As (V). Methylarsenic acids may be reduced to corresponding methylarsines with sodium borohydride after which separation permits specific detection of these arsenic compounds. The most sensitive and selective methods combine reduction, separation, and emission type detectors. The intensity of arsenic atomic emission lines is observed. This type of detector provides a lower limit of detection down to 0.02 ng As per sample. The methods have been applied to a variety of environmental samples.

Air Pollution↗
PubMed1973

Methylated forms of arsenic in the environment.

Environmental samples were analyzed for arsenate and arsenite ions and the methylarsenic acids in nanogram amounts. Dimethylarsinic acid and methylarsonic acid were found in natural waters, bird eggshells, seashells, and human urine.

Animals↗