Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rates on Spacelab-3 was the first mission to provide hand-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferon production by spleen cells, defective release of growth hormone by somatotrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythopoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity

Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rats on Spacelab-3 was the first mission to provide hands-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferom production by spleen cells, defective release of growth hormone by somatrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythropoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity

The effect of protein structural configuration on the free enzyme kinetic behavior of urease /

Current enzyme kinetic equations are inadequate for modelling enzymatic reactor systems because they fail to take into account the interactions between that various process parameters. They also are unable to predict reaction rates in complex solute systems. A quasi-native kinetic model was developed that predicts enzyme activity by examining the effect of solute addition on the overall protein structure. The theory was tested using the enzyme urease (urea aminohydrolase EC 3.5.1.5).The quasi-native model was found to accurately predict both the activation and inhibition phenomena observed with urease and could also predict enzymatic activity in complex solute systems. The quasi-native isomerization constant was shown to be a function of hydrophobic effects characterized by the Sechenov theory and electrostatic effects characterized by the DeBye-Huckel theory. The Sechenov constant was found to be independent of temperature and pH.The urease denaturation rate constant displayed a response to solute addition similar to that observed with the quasi-native isomerization equilibrium constant. However, the effect of pH on urease kinetics was a complex function of the ionization of active-site ligands and enzyme surface charge interactions

DNA Probe for Beta-Hemolytic Group B Streptococcus: Diagnostic Accuracy in Threatened Preterm Labor

Objective: To determine the diagnostic accuracy of a DNA probe for beta-hemolytic group B Streptococcus (GBS) in women with threatened preterm labor. Study Design: Two identical vaginal/perianal samples were collected from 75 pregnant women who were being evaluated for threatened preterm labor. One sample was managed in the traditional manner, with direct plating onto blood agar followed by plating after 8 and 24 hours of LIM broth enhancement. The gold standard was 24 hours of LIM broth enhancement followed by blood agar plating. The second sample was placed in LIM broth, and DNA probe testing was performed after incubation for 8 and 24 hours. Results: The prevalence of GBS colonization by the gold standard culture was 32%. After 8 hours of incubation in LIM broth, the DNA probe had poor sensitivity (79%); however, after 24 hours of incubation in LIM broth the DNA probe sensitivity rose to 96%. The DNA probe demonstrated only one false negative result after 24 hours of LIM broth enhancement. All DNA probe results were known 25 hours after sample collection. Conclusion: This DNA probe gave results nearly identical to those of standard cultures and allowed a substantial saving of time

DNA Probe for Beta-Hemolytic Group B Streptococcus: Diagnostic Accuracy in Threatened Preterm Labor

Objective: To determine the diagnostic accuracy of a DNA probe for beta-hemolytic group B Streptococcus (GBS) in women with threatened preterm labor. Study Design: Two identical vaginal/perianal samples were collected from 75 pregnant women who were being evaluated for threatened preterm labor. One sample was managed in the traditional manner, with direct plating onto blood agar followed by plating after 8 and 24 hours of LIM broth enhancement. The gold standard was 24 hours of LIM broth enhancement followed by blood agar plating. The second sample was placed in LIM broth, and DNA probe testing was performed after incubation for 8 and 24 hours. Results: The prevalence of GBS colonization by the gold standard culture was 32%. After 8 hours of incubation in LIM broth, the DNA probe had poor sensitivity (79%); however, after 24 hours of incubation in LIM broth the DNA probe sensitivity rose to 96%. The DNA probe demonstrated only one false negative result after 24 hours of LIM broth enhancement. All DNA probe results were known 25 hours after sample collection. Conclusion: This DNA probe gave results nearly identical to those of standard cultures and allowed a substantial saving of time

DNA Probe for Beta-Hemolytic Group B Streptococcus: Diagnostic Accuracy in Threatened Preterm Labor

Objective: To determine the diagnostic accuracy of a DNA probe for beta-hemolytic group B Streptococcus (GBS) in women with threatened preterm labor. Study Design: Two identical vaginal/perianal samples were collected from 75 pregnant women who were being evaluated for threatened preterm labor. One sample was managed in the traditional manner, with direct plating onto blood agar followed by plating after 8 and 24 hours of LIM broth enhancement. The gold standard was 24 hours of LIM broth enhancement followed by blood agar plating. The second sample was placed in LIM broth, and DNA probe testing was performed after incubation for 8 and 24 hours. Results: The prevalence of GBS colonization by the gold standard culture was 32%. After 8 hours of incubation in LIM broth, the DNA probe had poor sensitivity (79%); however, after 24 hours of incubation in LIM broth the DNA probe sensitivity rose to 96%. The DNA probe demonstrated only one false negative result after 24 hours of LIM broth enhancement. All DNA probe results were known 25 hours after sample collection. Conclusion: This DNA probe gave results nearly identical to those of standard cultures and allowed a substantial saving of time