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Biomedical subjects

A C Scott

Publications and source records attributed to A C Scott.

At least 91 records · Page 5Linked to original sources
PubMed1980

Computer-assisted customized antimicrobial dosages.

The use of a computer-based consultation program to customize dosage regimens of antimicrobials for patients with meningitis or bacteremia is described. Using clinical and laboratory information entered by the user, the program determines causative organisms, recommends therapeutic regimens, and generates a graph depicting the expected blood level of each drug as a function of time. During therapy selection, the program considers the site of infection, the susceptibility of the organism to antibiotics, and the patient's clinical status and drug history. Individualized pharmacokinetic values allow for dosage adjustments in renal failure and estimation of blood levels. If renal impairment is present, dosage regimens for drugs excreted by the kidneys are adjusted to assure the desired steady-state blood levels. To help in selection of the optimal regimen, estimated blood levels for each regimen are graphed along with the minimum inhibitory concentration for the organism and the toxic level of the drug. A bulit-in knowledge base in conjunction with patient-specific information enables the computer program to determine appropriate treatment specific to a patient's age, renal function, and prior drug reactions.

Adult↗
PubMed1979

Antimicrobial selection by a computer. A blinded evaluation by infectious diseases experts.

An evaluation of a computer-based consultation system called MYCIN was made. Eight independent evaluators with special expertise in the management of meningitis compared MYCIN's choice of antimicrobials with the choices of nine human prescribers for ten test cases of meningitis. MYCIN received an acceptability rating of 65% by the evaluators; the corresponding ratings for acceptability of the regimen prescribed by the five faculty specialists ranged from 42.5% to 62.5%. The system never failed to cover a treatable pathogen while demonstrating efficiency in minimizing the number of antimicrobials prescribed. The study design may be useful in assessing the performance of other computer-based clinical decision-making systems.

Adult↗
PubMed1979

Evaluating the performance of a computer-based consultant.

The performance of a computer-based clinical consultation system is evaluated. The program, called MYCIN, is designed to function as an aid for infectious disease diagnosis and therapy selection, with an initial emphasis on bacteremias. The evaluation methodology is discussed, as well as the difficulties encountered in attempting to evaluate clinical judgments. Specialists in infectious diseases judged MYCIN's final therapy recommedation, and intermediate conclusions about the significance of the infection and identity of infecting organisms. The evaluation techniques described may be useful in assessing the performance of other clinical decision aids. Results of the evaluation show that the program's therapy recommedations meet Stanford experts' standards of acceptable practice 90.9% of the time (table 2), with some variation noted both among individual experts and between Stanford experts and others (tables 1, 2).

Animals↗
PubMed1978

Alterations in hepatic fine structure after chronic exposure of rats to dexamethasone.

The objective of this study was to determine the effects of chronic dexamethasone (DEX) administration on hepatic ultrastructure and to correlate these changes with plasma lipoprotein levels. Electron microscopic studies were made of hepatocytes from male rats killed 1, 3 and 5 days after DEX (2 mg, twice per day) administration. Three days after treatment plasma lipoprotein levels were highest and hepatocytes contained regions of the cytosome rich in elements of the smooth endoplasmic reticulum (SER). Osmiophilic particles were present in the tubules and vesicles of the SER, in the saccules and vacuoles of the Golgi complex, in secretory vesicles near the cell surface and in the space of Disse. DEX treatments also caused hepatocytes to accumulate tightly packed masses of beta-particles of glycogen in some regions of the cell while other areas displayed dispersed glycogen particles that were associated with the SER. These observations are consistent with the hypothesis that glucocorticoids 1. cause an elevation of plasma lipoprotein levels by increasing hepatic synthesis and secretion of VLDL, which involves the sequential participation of the ER, the Golgi complex and exocytosis of VLDL-containing vacuoles into the space of Disse, and 2. produce a change in the nature of the association of glycogen particles with the SER membranes in response to the physiological state of the animal.

Animals↗
PubMed1977

Organization of sequences of avian globin mRNA.

Formamide polyacrylamide gel electrophoresis shows that chicken globin mRNA contains about 6.50 nucleotides, and since only 435 of these code for globin, a further 215 are not translated, and their function and position are not known. This work has produced the following conclusions. 1. 45-50 of these untranslated nucleotides are present as poly (A) at the 3' terminus. 2. The 3' untranslated region of chicken globin mRNA is at least 90 nucleotides in length. This minimal estimate is based on data derived from hybridization of defined lenghts of chicken globin cDNA to rabbit globin mRNA. The percentage of avian globin cDNA sequences which hybridize to rabbit globin mRNA is directly proportional to the length of the cDNA in each case. This relationship holds for lengths of cDNA from 115 up to 620 nucleotides. The low percentage homology for short cDNA molecules is not due to their being short per se. In homologous mRNA excess hybridizations (chicken cDNA/chicken mRNA), all cDNA preparations were completely protected from S1 nuclease digestion. 3. It is probable that there is greater evolutionary divergence in the 3' untranslated region of chicken and rabbit globin mRNA when compared with the coding regions of these molecules; The combined data is sued to formulate a regional map of chicken globin mRNA,

Animals↗
PubMed1976

Reiteration frequency of the gene for tissue-specific histone H5 in the chicken genome.

Chicken erythroid cells contain a tissue specific histone known as H5 in addition to the five major histone species found in other organisms. The mRNA coding for this histone has been isolated by indirect immunoprecipitation from immature, non-dividing reticulocytes in which this is the only histone synthesised. The mRNA has been modified by the enzymatic addition of a 3' polyadenylic acid tract, and transcribed into complementary DNA (cDNA) using the RNA-dependent DNA-polymerase from avian myeloblastosis virus. Studies on the hybridisation of this cDNA indicate that the gene coding for the H5 histone is reiterated 10 times in the chicken genome.

Alleles↗
PubMed1976

Computerized consultation system for selection of antimicrobial therapy.

Mycin, a computer-based consultation system which provides to physicians antimicrobial therapy recommendations for patients with bacterial infections, is described. The consultation program arrives at therapeutic decisions using a built-in knowledge base as well as patient data entered by the physician. The system is capable of explaining its recommendations and answering questions about its reasoning process. The system's knowledge can be updated and corrected easily by infectious disease experts. At present the system is operational within a research setting; its routine use in a clinical setting will require further evaluation of its reliability and effectiveness.

Anti-Infective Agents↗
PubMed1975

Infectious bursal disease agent: morphology by negative stain electron microscopy.

The virus of infectious bursal disease of chickens was studied by immune electron microscopy. Negatively-stained preparations revealed morphological similarities with both the bluetongue virus group, and the virus of infectious pancreatic necrosis of trout. Results indicated that the small particle found in such preparations is a degradation product of the large particle.

Centrifugation, Density Gradient↗