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H Conn

Publications and source records attributed to H Conn.

27 records · Page 2Linked to original sources

Oxygen content determined by acrylamide polymerization: screening of anticancer agents, generation of oxyhemoglobin dissociation curves, and potential applications.

Many investigators have endeavored to accurately measure oxygen content produced or consumed from substrates or tissues. Most of the techniques currently available are time consuming or exceedingly complex. Many require expensive apparatus and demand the skills of a highly trained technician. We have deveoloped a rapid and sensitive method of measuring oxygen content or consumption. This method is based upon the time for polymerization of acrylamide gels. The time of acrylamide polymerization is directly proportional to the oxygen content of the test medium. We have used this method to generate oxyhemoglobin dissociation curves which closely resemble those published by Severinghaus and Duvelleroy, as well as those we determined by the conventional Van Slyke analysis. We have also used this method to measure the oxygen consumption of tumor cells and to evaluate the effects of Actinomycin, cyclohexamide and cytosine arabinoside on Walker 256 ascites tumor. The results correlate with the known in vivo effects of these drugs on this tumor cell line. Therefore, because of its sensitivity and adaptability this method may be useful in a variety of clinical and biological situations.

Acrylamides↗

Continuous long-term intra-arterial infusion in the unrestrained rabbit.

A technique for the catheterization and intra-arterial infusion of the common carotid artery of the rabbit utilized a simple swivel apparatus, an acrylic head mount, and a silicone rubber sleeve. This method was used for continuous intra-arterial infusion in 29 unrestrained rabbits for periods up to 61 days.

Animals↗

Luft's disease. Further biochemical and ultrastructural studies of skeletal muscle in the second case.

In the second known case of non-thyroidal hypermetabolism (Luft's disease), there were large areas of mitochondrial aggregates in all fibers. Many mitochondria were abnormally large and contained packed cristae. In isolated mitochondrial fractions, studies of oxidative phosphorylation showed defective respiratory control and normal phosphorylation capacity ("loose coupling"). Spectra and content of cytochromes were normal. Basal ATPase activity was seven times greater than normal and poorly stimulated by 2,4-dinitrophenol. The rate of energy-dependent calcium uptake by isolated mitochondria was normal, but the amount of calcium accumulated was much decreased. Calcium could not be retained and was spontaneously released into the medium within 30 seconds. "Recycling" of calcium between mitochondria and cytosol may take place in vivo and result in sustained stimulation of respiration and loose coupling.

Adult↗

Experimental evaluation of coronary infusates in dogs.

In a study involving dogs, a coronary infusate containing a variety of substances including cardiac substrates, metabolic inhibitors, membrane stabilizers, electrolytes, and anticoagulants was evaluated in terms of protection afforded to the myocardium for up to 90 minutes of normothermic anoxic arrest. Electron microscopical studies and tissue adenosine triphosphate measurements revealed this coronary infusate to be considerably beneficial to the myocardium. Infused myocardium was better preserved compared to myocardium that was not infused or infused with two other "control" infusates. The individual components of our infusate are known cardiac preservatives. The rationale for combining a number of them in our infusate is to produce an additive or synergetic effect through beneficial intervention at several points in the cardiac metabolic cycle. This objective appears to have been fulfilled under the conditions of the present experiment.

Adenosine Triphosphate↗

Acrylamide polymerization: new method for determining the oxygen content in blood.

A new principle for determining the oxygen content of 0.1-milliliter blood samples has been developed, based on measurement of the delay in gelation during copolymerization of acrylamide and bisacrylamide initiated by free radicals. The logarithm of this time interval is linearly proportional to the oxygen content of the blood sample over the range 0 to 22 milliliters of oxygen per 100 milliliters of whole blood. Physiological variations of pH and pCO(2) do not affect the sensitivity of the assay.

Acrylamides↗