Immobilization of polar bears with carfentanil.
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Animals↗
Biomedical subjects
L J Lee
Publications and source records attributed to L J Lee.
Cloning and expression of the beta-D-phosphogalactoside galactohydrolase gene of Lactobacillus casei in Escherichia coli K-12.
Lactose metabolism in Lactobacillus casei 64H is associated with the presence of plasmid pLZ64. This plasmid determines both phosphoenolpyruvate-dependent phosphotransferase uptake of lactose and beta-D-phosphogalactoside galactohydrolase. A shotgun clone bank of chimeric plasmids containing restriction enzyme digest fragments of pLZ64 DNA was constructed in Escherichia coli K-12. One clone contained the gene coding for beta-D-phosphogalactoside galactohydrolase on a 7.9-kilobase PstI fragment cloned into the vector pBR322 in E. coli strain chi 1849. The beta-D-phosphogalactoside galactohydrolase enzyme isolated from E. coli showed no difference from that isolated from L. casei, and specific activity of beta-D-phosphogalactoside galactohydrolase was stimulated 1.8-fold in E. coli by growth in media containing beta-galactosides. A restriction map of the recombinant plasmid was compiled, and with that information, a series of subclones was constructed. From an analysis of the proteins produced by minicells prepared from transformant E. coli cells containing each of the recombinant subclone plasmids, it was found that the gene for the 56-kilodalton beta-D-phosphogalactoside galactohydrolase was transcribed from an L. casei-derived promoter. The gene for a second protein product (43 kilodaltons) was transcribed in the opposite direction, presumably under the control of a promoter in pBR322. The relationship of this second product to the lactose metabolism genes of L. casei is at present unknown.
Cloning, Molecular↗
Presence of a single enzyme catalyzing the pyrophosphorolysis of UDP-glucose and UDP-galactose in Bifidobacterium bifidum.
The enzyme preparation catalyzing the pyrophosphorolyses of UDP-glucose and UDPgalactose almost at the same rate was purified about 900-fold from Bifidobacterium bifidum grown on glucose medium. The two activities were always associated with each other, and their activity ratio was always constant throughout the purification steps. The final preparations was revealed homogeneous by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. There was no significant difference in thermal stabilities of the two activities. From these results it was concluded that the UDPglucose and UDPgalactose pyrophosphorylase activities in B. bifidum are catalyzed by a single enzyme protein.
Actinomycetaceae↗
Effect of organ perfusion on renal drug transport. Application to furosemide in the isolated perfused rat kidney.
Angiotensin II was used as a probe to study the effect of changes in perfusate flow rate on the renal clearance parameters of furosemide in the isolated perfused rat kidney. Drug studies were performed in three rats with no angiotensin II present in the perfusate (treatment I) and in three rats with a 2.7 ng/min infusion of angiotensin II into the perfusate (treatment II). Furosemide was introduced into the recirculating perfusate at an initial concentration of 3.5 micrograms/ml and was assayed using HPLC. The protein binding of furosemide in perfusate was determined by equilibrium dialysis. Angiotensin II was found to have a dramatic effect on the renal hemodynamics, resulting in a 42% decrease in perfusate flow, a 27% decrease in GFR, and a 25% increase in filtration fraction. Values for the fractional excretion of glucose were very low and consistent, with or without angiotensin II (3.0-3.5%). Although the fraction unbound of furosemide was unchanged between treatments (0.770 for treatment I vs. 0.695% for treatment II), the renal and secretion clearances of furosemide were reduced by about 30% in the presence of angiotensin II. However, if the renal clearance (CLr) was corrected for free fraction (fu) and glomerular filtration rate (GFR) [ER = CLr/(fu.GFR)], there was no difference between the excretion ratio (ER) values of furosemide after the two treatments (29.0 for treatment I vs. 29.6 for treatment II). These results imply that the altered clearance parameters of furosemide are more likely the consequence of a reduction in functional nephron mass rather than a change in intrinsic secretory transport per unit mass of nephron.
Angiotensin II↗
Penetration of levofloxacin into lung tissue after oral administration to subjects undergoing lung biopsy or lobectomy.
STUDY OBJECTIVE: To evaluate the pulmonary tissue distribution of levofloxacin, the new once-daily fluoroquinolone, after a single 500-mg oral dose. DESIGN: Open-label study. SETTING: One pulmonary clinic and two university-affiliated teaching hospitals. PATIENTS: Eighteen adults undergoing lung biopsy or lobectomy. INTERVENTIONS: Levofloxacin plasma and lung tissue concentrations were determined by high-performance liquid chromatography with fluorescence detection. Lung tissue levofloxacin concentrations were corrected for blood contamination by measuring hemoglobin. MEASUREMENTS AND MAIN RESULTS: After a single 500-mg oral dose, concentrations of levofloxacin in lung tissue consistently exceeded those in plasma at every time point over the 24-hour sampling period, with tissue:plasma penetration ratios of 2.02 (2-3 hrs), 5.02 (4-6 hrs), 5.13 (11-17 hrs), and 4.13 (22-25 hrs). The mean penetration ratio over the 24-hour sampling period was 3.95 (range 1.06-9.98). Lung tissue concentrations of levofloxacin also exceeded minimum inhibitory concentration values for most community-acquired respiratory tract pathogens over the 24 hours. CONCLUSION: This study supports clinical evaluation of levofloxacin as once-daily oral therapy for community-acquired lower respiratory tract infections.
Administration, Oral↗