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Biomedical subjects

A Peterson

Publications and source records attributed to A Peterson.

8 recordsLinked to original sources
PubMed1978

Degradative behavior of a new bronchodilator, carbuterol, in aqueous solution.

The degradation kinetics of carbuterol in aqueous solution were investigated at 85 degrees and constant ionic strength over the pH 0.25--13.3 range under anaerobic conditions. The results demonstrated a complex kinetic pattern involving specific acid and specific base catalyses at the pH extremes. Degradation resulted primarily from intramolecular catalysis and indicated that both the protonated and unprotonated phenolic groups participated in the reaction. High-pressure liquid chromatography was used to isolate carbuterol and its degradation product. Mass spectrometric examination showed that the degradation product was a cyclized derivative formed by intramolecular attack of the phenoxy group on the ureido carbonyl with ammonia expulsion. The apparent activation energy for carbuterol at pH 4.0 and 10.0 was 22.3 and 11.7 kcal/mole, respectively. The agreement between the calculated theoretical pH--rate profile and the experimental points supports the hypothesis presented concerning the reactions involved in carbuterol degradation.

Buffers↗
PubMed1978

The effect of glucagon in animals on chronic propranolol therapy.

Eleven adult mongrel dogs were divided into two groups. Group 1 animals served as controls and Group 2 received propranolol (6 mg/kg/day) orally in divided doses for 15 to 21 days. Prior to cardiopulmonary bypass, cardiac output, first derivative of left ventricular pressure (dp/dt), peak systolic pressure, heart rate, and central venous pressure were recorded. The animals were then placed on cardiopulmonary bypass and subjected to 30 minutes of global ischemia at the myocardial temperature of 32 degrees C. Following cessation of cardiopulmonary bypass the baseline studies were repeated. In Group 2 animals following the repeat studies, glucagon was administered at a rate of 0.13 microgram/kg/min. The cardiac index and dp/dt were decreased by 43.3% (p less than 0.001) and 40.5% (p less than 0.001) in comparison to Group 1 animals. In Group 2 dogs, after bypass and glucagon infusion, cardiac index increased by 38% (p less than 0.02), dp/dt rose by 78% (p less than 0.05), and peak systolic pressure increased by 24.8% (p less than 0.05). These studies show the benefit of glucagon in the treatment of low cardiac output in the presence of beta-adrenergic blockade.

Animals↗
PubMed1978

Treatment of caustic injuries of the esophagus: a ten year experience.

The methods of managing 32 patients sustaining caustic injuries to the esophagus are assessed. Treatment of these patients must be individualized according to the type of caustic ingested, the degree of burn and other clinical signs. While an aggressive approach is favored for second and third-degree burns in the form of early esophago-gastrectomy with subsequent colon interposition, operation is not necessary. In all patients, particularly those with first-degree burns. The use of antibiotics is recommended as soon as the diagnosis of esophageal injury is established. The efficacy of steroids in preventing stricture formation, especially with third-degree burns, is questioned.

Adult↗
PubMed1978

Cell surface antigens containing beta2-microglobulin as the common subunit.

beta2-Microglobulin, which was first discovered in various biological fluids, has been shown to be the common subunit of the human HLA-A,B,C antigens. In the mouse beta2-microglobulin is associated with H-2K, D and L antigens and with TL and Qa-2 antigens, beta2-microglobulin and the heavy HLA antigen chains are similar in structure to the immunoglobulins and it is suggested that the two types of molecules have had an interrelated evolution. Data are also presented which suggest that the structural similarity between transplantation antigens and immunoglobulins may be paralleled by a functional similarity as well.

Animals↗
PubMed1978

Nitroglycerin infusion during infrarenal aortic cross-clamping in dogs: an experimental study.

The effects of an intravenous infusion of nitroglycerin on cardiac index and peripheral vascular resistance during infrarenal aortic cross-clamping were determined in normal animals and in animals subjected to low cardiac output state. Both groups of untreated animals demonstrated progressive fall in cardiac index with a rise in total peripheral resistance during infrarenal aortic cross-clamping. The infusion of nitroglycerin during the period of aortic cross-clamping prevented the increase in total peripheral resistance and therefore prevented the progressive fall in cardiac index that occurred in untreated animals. In the animals with depressed myocardial function, the infusion of nitroglycerin produced a 44% increase in cardiac index during aortic cross-clamping. The results of this study showed that the infusion of nitroglycerin during abdominal aortic cross-clamping can prevent adverse cardiovascular sequelae from occurring and should be used in patients undergoing abdominal aortic resection, especially those with impairment of left ventricular function.

Animals↗
PubMed1977

"What's wrong with my baby?".

The birth of a child with any developmental disability is an occasion of marked trauma to parents. Early, honest and frank counseling is imperative, and the family physician can play a unique role in this counseling process. When the physician is not knowledgeable in a paretcular case, he or she should seek expert help and fully utilize available community services.

Communication↗