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Biomedical subjects

R Lee

Publications and source records attributed to R Lee.

At least 361 records · Page 20Linked to original sources
PubMed1980

Production of 7.6-minute potassium-38 for medical use.

A method is described for generating 20--30 mCi of 7.6-min potassium-38 by means of a small cyclotron. Sodium chloride is mounted on a water-cooled tantalum plate, by evaporation from an aqueous solution. It is bombarded with 14.7 MeV helium-4 ions, at 50 microA. The K-38 is produced free of other radionuclides. For intravenous injection the bombarded NaCl is dissolved in sufficient pyrogen-free water to make an isotonic saline solution, which then is sterilized by filtration. Other methods of production investigated were the bombardment of: carbon tetrachloride with He-4 ions; calcium oxide with 7.8-MeV deuterons; and potassium chloride with 23-MeV He-3 ions. These gave products that were unsuitable for clinical applications. Chiefly because of the short half-life of K-38, the whole-body radiation exposure is estimated to be only about 12 mrad/mCi, and exposures to the heart and kidneys are approximately ten times greater.

Animals↗
PubMed1980

Retinal changes in rats flown on Cosmos 936: A cosmic ray experiment.

Ten rats, five centrifuged during flight to simulate gravity and five stationary in flight and experiencing hypogravity, orbited the Earth. No differences were noted between flight-stationary and flight-centrifuged animals, but changes were seen between these two groups and ground controls. Morphological alterations were observed comparable to those in the experiment flown on Cosmos 782 and to the retinal cells exposed to high-energy particles at Berkeley. Affected cells in the outer nuclear layer showed swelling, clearing of cytoplasm, and disruption of the membranes. Tissue channels were again found, similar to those seen on 782. After space flight, preliminary data indicated an increase in cell size in montages of the nuclear layer of both groups of flight animals. This experiment shows that weightlessness and environmental conditions other than cosmic radiation do not contribute to the observed damage of retinal cells.

Animals↗
PubMed1979

Fluoroscopic investigation of pharyngeal function in the horse.

Videofluoroscopy was used to study the deglutition reflexin 2 horses believed, on the basis of endoscopic and clinical examination, to have normal pharyngeal and laryngeal function. The reflex was found to be the same as that described in man and in the rabbit. A feature of deglutition in the horse was the temporary increase in size of the auditory tube diverticuli (gluttural pouches) as a result of contraction of the pharyngeal muscles.

Animals↗
PubMed1979

The effect of laryngoplasty on pharyngeal function in the horse.

Using fluoroscopic techniques and videotape recordings, a study of normal deglutition was made in 2 ponies. Paryngeal function was studied at intervals after laryngoplasty on 1 animal and after a sham technique on the other. Two clinical cases of laryngeal paralysis, which had been treated by laryngoplasty, were also examined. In the 2 experimental ponies, liquid food passed into the lower respiratory tract post-operatively. One of the clinical cases appeared to swallow solid food normally, but some food material entered the larynx of the other horse. It is suggested that pharyngeal dysfunction, as well as over-abduction of the arytenoid cartilage, might be involved in causing the chronic post-operative cough which the experiment was designed to investigate.

Animals↗
PubMed1979

Paying for physician services under Medicare and Medicaid.

Public systems for physician reimbursement aim to reconcile two disparate objectives: ensuring availability of services to the poor and aged; and keeping rates of cost increase within acceptable limits. Several interesting--and unorthodox--policy simulations of physician pricing behavior are investigated through econometric estimation. Current arrangement for paying physicians are fraught with difficulties. The objectives of Medicare and Medicaid are not well served.

Aged↗
PubMed1978

Pharmacokinetics of oral cephalosporins: cephradine cephalexin.

A crossover experiment was utilized to compare the pharmacokinetics of a 1-g dose of cephalexin tablets, cephalexin capsules, or cephradine capsules in nine normal human volunteers. These antibiotics were administered as three formulations: two 500-mg capsulin every 6 hr for five doses, and one 1000-mg tablet of cephalexin every 6 hr for five doses. Pharmacokinetic parameters in the experimental groups showed no statistical differences (p greater than 0.1), indicating that these drugs are equivalent pharmacokinetically.

Administration, Oral↗
PubMed1978

Counseling juvenile offenders: an experimental evaluation of Project Crest.

Thirty randomly selected juvenile delinquents receiving a dual treatment approach of community outreach counseling services (Project CREST) and probationary supervision were compared over a 6-month period with a control group of 34 delinquents receiving only probationary supervision. The CREST group demonstrated significant improvements over the control group on total acts of misconduct (p less than .05) and monthly misconduct rates (p less than .025). These findings are discussed in light of previous evaluations of the CREST model.

Adolescent↗
PubMed1978

On unstable cohomology classes of SL(Z).

From algebraic K-theory, we show that there exists a spectral sequence that has real cohomology of SL(n)(Z) as its E(1)-terms and converges to the tensor product of a polynomial algebra and an exterior algebra. On the basis of this spectral sequence, we discovered several families of real unstable cohomology classes of SL(n)(Z).

Journal Article↗
PubMed1978

Hyperchloremic metabolic acidosis in diabetes mellitus: a case report and discussion of pathophysiologic mechanisms.

A 21-year old woman with poorly controlled diabetes mellitus was examined for persistent hyperchloremic metabolic acidosis. There was no evidence of ingestion of hydrochloric acid or its equivalent. Gastrointestinal loss of bicarbonate was absent. Proximal tubular bicarbonate reabsorption and distal nephron hydrogen-ion secretion were normal. Ammonia and net acid excretions were high, and thus there was no obvious cause for this acidosis. Further study revealed a very large loss of beta-hydroxybutyrate in the urine that closely approximated net acid excretion. This loss of potential bicarbonate was the principal cause for the hyperchloremic metabolic acidosis. Phosphate, urate, and beta-hydroxybutyrate fractional excretions were all abnormally high. Generalized aminoaciduria was also present, but the renal handling of glucose and bicarbonate was normal. With improved control of her diabetes, the generalized aminoaciduria disappeared, the urine beta-hydroxybutyrate loss ceased, the fractional excretions of phosphate and urate approached normal, and the acidosis was rapidly corrected.

Adult↗
PubMed1978

Reference ovine serum chemistry values.

Twenty-five serum chemistry values were determined on 18 female sheep. These average values were obtained using current semiautomated analytical techniques, with all enzyme measurements reported in international units. Where possible, these results were compared with those of 4 other investigators. This compilation will provide a set of reference values which can be used for comparison with results obtained from current commercial clinical laboratories.

Animals↗