Saphronia R Johnson

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We compared mdx and C57BL10 anterior tibial muscle force in situ (single pulse, multiple pulse, staircase, posttetanic potentiation, and fatiguing stimulation patterns) to define muscle strength, physiology, and fatigue resistance. The relatively hypertrophied mdx muscle showed: reduced strength (N/cm2), an increased twitch-tetanus ratio, and resistance to(More)
We studied the effects of aerosolized as well as intravenous infusion of acetylcholine on bronchial blood flow in six anesthetized sheep. Intravenous infusion of acetylcholine, at a dose of 2 microg/kg, increased bronchial blood flow from 45 +/- 15 (SE) to 74 +/- 30 ml/min, and vascular conductance increased by 76 +/- 22%. In contrast, aerosolized(More)
Improved Vibrio cholerae donors were constructed by introducing the ampicillin transposon, Tn1, into both the conjugative plasmid, P, and the bacterial chromosome to provide "portable regions of homology." The resulting Tfr (Transposon-facilitated recombination) donors transferred genes at high frequency from origins specified by the chromosomally inserted(More)
In anesthetized sheep, we measured bronchial blood flow (Qbr) by an ultrasonic flow probe to investigate the interaction between inhaled nitric oxide (NO; 100 parts/million) given for 5 min and 5 ml of aerosolized isoetharine (1.49 x 10(-2) M concentration). NO and isoetharine increased Qbr from 26.5 +/- 6.5 to 39.1 (SE) +/- 10.6 and 39.7 +/- 10.7 ml/min,(More)
A single hind limb was irradiated with 12, 18, 24, or 30 Gy in mdx and C57 mice aged 12, 21, or 42 days to determine regeneration inhibition dose-response curves in different aged dystrophic mice and to characterize radiation side-effects in normal mice. The anterior tibial muscle mass (8 weeks postirradiation) and percent central nucleated (i.e.,(More)
We studied the dose-dependent effects of inhaled isoetharine HCl, a beta-adrenergic bronchodilator (2.5, 5.0, 10.0, and 20.0 mg), on bronchial blood flow (Qbr) in anesthetized sheep. Isoetharine resulted in a dose-dependent increase in Qbr. With a total dose of 17.5 mg, Qbr increased from baseline values of 22 +/- 3.4 (SE) to 60 +/- 16 ml/min (P < 0.001),(More)
Thymidylate synthase (TS) is a well-validated cancer target that undergoes conformational switching between active and inactive states. Two mutant human TS (hTS) proteins are predicted from crystal structures to be stabilized in an inactive conformation to differing extents, with M190K populating the inactive conformation to a greater extent than A191K.(More)