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Biomedical subjects

R M Knapp

Publications and source records attributed to R M Knapp.

At least 19 recordsLinked to original sources
PubMed1993

In situ growth and activity and modes of penetration of Escherichia coli in unconsolidated porous materials.

Statistically reliable data on the in situ rates of growth, substrate consumption, and product formation are required to test the validity of the mathematical models developed for microbially enhanced oil recovery and in situ bioremediation processes. A simple, replicable porous-core system that could be aseptically divided into sections at various times was developed to follow the kinetics of microbial growth and metabolism in situ. This core system was used to study the kinetics of growth and the mode of penetration of strains of Escherichia coli through anaerobic, nutrient-saturated, fine Ottawa sand (permeability of 7.0 microns2 and porosity of 37%) under static conditions. The in situ rate of growth of a wild-type, motile, chemotactic strain, RW262, was two times slower inside cores than it was in liquid cultures. The mode of metabolism of galactose by strain RW262 was not altered inside cores, as acetate was the only product detected either inside the cores or in liquid cultures. Without applied advective force, strain RW262 grew exponentially and moved through cores at a rate of about 0.1 m/day. The cell population moved through cores in a band-like fashion, as the front of the moving cells consisted of high cell concentrations (greater than 10(5) cells per ml). Until the breakthrough of the cells occurred, galactose consumption and acetate production were observed only in the proximal sections of the core, showing that the cell propagation preceded the complete depletion of the substrate or the accumulation of large amounts of products.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1985

Graduate medical education: financing at the crossroads.

Teaching hospitals are concerned about the new competitive environment because their costs are generally higher than those of nonteaching hospitals. Many of the higher costs of teaching hospitals derive from their educational programs, the nature of the patient diagnostic case mix; losses on charity care; and their role in the introduction of new and more effective methods for prevention, diagnosis, and treatment of illness. All of these functions are important to the missions of teaching hospitals, and all make teaching hospitals more expensive to operate than nonteaching hospitals. While a solution to the problem of financing graduate medical education will not ensure teaching hospital financial health, a solution to the financing of graduate medical education will provide a more equitable environment in which teaching hospitals can compete. The basic question to be answered in the price competitive environment is, "can the teaching hospital continue to attract patients at a competitive price and maintain financial support for its educational programs at current levels?" Teaching hospitals are a diverse group of highly complex institutions performing medical education and research services for the nation and providing both basic and tertiary patient care. The current emphasis on reexamining national policies in light of more limited public resources places teaching hospitals and their vital activities at significant risk if their special nature and role are not appreciated.

Education, Medical, Graduate↗
PubMed1985

Educational evaluation. The first step toward understanding and remediation of central auditory disorders.

Of all the problems experienced by children with learning disabilities, a language disorder may be the most detrimental to school performance. Because the problems of a child with a language disorder are frequently not recognized until he begins school, it is important that the educational clinician, teacher, related professional, and parents understand what a central auditory disorder is, that it may manifest itself as language disorder, and the way it can academically and emotionally affect a child. Evaluation and identification of a child with a central auditory disorder is vital at an early stage of development; however, testing, while it appears simple, is an extremely complex process and is not always exact. Therefore, the educational clinician must be skilled and understand the frailties which exist in the test instrument and the testing situation. It must be remembered, also, that testing in only part of the diagnostic procedure. Organized, perceptive classroom observations are essential. These must be followed by multidisciplinary meetings that generate remedial procedures and directions to be taken by parents and teachers. Finally, parents must be accepted by professionals as reasonable, concerned, and able to offer knowledgeable insight into their child's learning problems. If a language disorder is suspected, professional help should be sought immediately. Truth is better than fiction or fantasy in helping a child become a happy, adjusted, productive human being.

Auditory Perceptual Disorders↗
PubMed1984

Serum bupivacaine concentrations in term parturients following continuous epidural analgesia for labor and delivery.

This study was undertaken to measure the blood concentrations of bupivacaine associated with a single loading dose followed by continuous epidural infusion for the management of the pain of labor and delivery with special reference to the potential for accumulation and toxicity. Four-milliliter venous blood samples were obtained every 15 min following the loading dose until delivery. If inadequate analgesia was observed just prior to delivery, an additional dose of bupivacaine was administered. Bupivacaine concentrations were measured using a double extraction technique followed by gas chromatographic analysis using a nitrogen-specific detector. Clearance, volume of distribution, and rate of absorption were estimated from the blood concentration time data and were 43.39 +/- 11.46 L/h, 67.56 +/- 17.66 L, and 8.97 +/- 3.69 h-1, respectively. Peak serum bupivacaine concentrations were 0.68 +/- 0.14 microgram/ml and occurred 0.58 +/- 0.25 h following administration of the loading dose. The duration of bupivacaine infusion was 3.42 +/- 0.80 h. Serum bupivacaine concentrations at delivery or just prior to administration of a supplemental delivery dose were significantly lower than the peak concentration in all patients (p less than 0.001). Fetal-to-maternal serum concentration ratios were found to be 0.44 +/- 0.16 for the six patients requiring a supplemental delivery dose and 0.44 +/- 0.13 for the six patients receiving bupivacaine only by infusion. The data reported here illustrate that epidural analgesia for labor and delivery achieved using a single 50-mg loading dose followed by a continuous infusion of 12.5 mg/h of bupivacaine will not result in maternal or fetal accumulation or toxicity.

Adult↗