ABSTRACT
Subsurface biobarriers can be conceived to attenuate the migration of pathogens by adhesion to mineral surfaces. Candidate biobarrier materials of varied surface characteristics (dolomite, alpha-alumina, silica, pyrophyllite, and Pyrax (a composite form of pyrophyllite, mica, and silica)) were tested for Escherichia coli adhesive capacity in macroscale continuous-flow columns. Atomic force microscopy (AFM) was used to determine nanoscale interaction energies. Predicted attractive interaction energies correlated well with macroscale adhesive behavior for tested E. coli strains. AFM measurements confirmed ExDLVO model predictions of attachment in the primary minima for E. coli O157:H7 and two environmental isolates E. coli (UCFL339 and UCFL-348) with MOPS conditioned Pyrax. In macroscale column experiments, pyrophyllite and Pyrax demonstrated significantly higher bacterial retention, higher deposition coefficients and lower initial cell breakthrough values for E. coli O157:H7 than did alpha-alumina, silica, or dolomite (pyrophyllite, 0.93, 3.56 h(-1), 3.2% ODo; Pyrax, 0.95, 3.73 h(-1), 2.8% ODo; alpha-alumina, 0.74, 1.60 h(-1), 33% ODo; silica, 0.63, 0.43 h(-1), 73% ODo; and dolomite, 0.33, 0.17 h(-1), 89% ODo, respectively). Bacterial hydrophilicity impacted cell retention in Pyrax columns with the relatively hydrophobic E. coli isolate UCFL-339 (0.99, 6.13 h(-1), 0.4% ODo) retained better than the more hydrophilic E. coli isolate UCFL348 (0.94, 3.70 h(-1), 3.6% ODo). The strong adhesive behavior of Pyrax was attributed to the hydrophobic (deltaGiwi = -32.4 mJ/m2) pyrophyllite component of the mineral. Vicinal water appears poised between the bacterial and the mineral surface during initial attachment. Overall, observed behavior of the various E. coli strains and the selected mineral surfaces was consistent with surface analyses, conducted at both the macro- and nanoscale.
Subject(s)
Bacterial Adhesion , Escherichia coli O157/physiology , Food Microbiology , Minerals/chemistry , Aluminum Oxide/chemistry , Aluminum Silicates/chemistry , Calcium Carbonate/chemistry , Escherichia coli O157/isolation & purification , Hydrophobic and Hydrophilic Interactions , Magnesium/chemistry , Microscopy, Atomic Force/methods , Silicon Dioxide/chemistry , Surface PropertiesABSTRACT
OBJECTIVE: To study the protective effect of RenShen compound and DanHuang compound on muscle atrophy caused by simulated weightlessness in rats. METHOD: Percentage and cross sectional area of fibers and ultrastructure of soleus (SOL) and gastrocnemius (GAS) were determined in 30 d tail suspended rats with or without administration of the medicine. RESULT: The percentage of type I fiber of SOL in RenShen (RS) group and DanHuang (DH) group increased by (13.5 +/- 0.96)% (P < 0.05) and (11.2 +/- 0.84)% (P < 0.05) respectively, and those of GAS showed only an increasing trend as compared with suspension control (SC). Cross sectional area of muscle fibers of SOL and GAS in both groups increased, especially in RS group (P < 0.05). The construction of SOL sarcomere in RS and DH groups was improved as compared with SC. CONCLUSION: RS and DH compounds can partially prevent muscle atrophy caused by tail suspension.
Subject(s)
Drugs, Chinese Herbal/pharmacology , Hindlimb Suspension/adverse effects , Muscle Fibers, Slow-Twitch/drug effects , Muscle, Skeletal/drug effects , Muscular Atrophy/prevention & control , Animals , Drug Evaluation, Preclinical , Drugs, Chinese Herbal/therapeutic use , Hindlimb Suspension/physiology , Muscle, Skeletal/ultrastructure , Muscular Atrophy/drug therapy , Panax/drug effects , Plants, Medicinal , Rats , Sarcomeres/drug effects , Weightlessness SimulationABSTRACT
The lymphocytes isolated from perfused or non-perfused circulations before, during, and after hyperthermic isolated limb perfusion (HILP) in the four patients with malignant melanoma were analysed for the expression of CD54 (ICAM-1), CD58 (LFA-3), CD4, CD8, HLA class I and class II in order to investigate the mechanism(s) of the activation of such immunocompetent cells as natural killer (NK)-cells or T-lymphocytes by HILP. It was thus found that the lymphocyte populations expressing CD54 increased significantly 1 day after HILP in the four patients examined. The lymphocyte populations expressing CD58 apparently increased. It was also found that the NK-cell and T-lymphocyte activities increased during or after HILP in the present four cases as observed previously in the other melanoma patients. These results indicate that our HILP system may augment the immunological activities through the mechanisms of the induction of CD54 or CD58 expression in the peripheral lymphocytes of the melanoma patients who receive HILP.
Subject(s)
Chemotherapy, Cancer, Regional Perfusion , Hyperthermia, Induced , Intercellular Adhesion Molecule-1/analysis , Lymphocytes/immunology , Melanoma/therapy , Skin Neoplasms/therapy , Adult , Aged , Extremities/blood supply , Female , Humans , Killer Cells, Natural/physiology , Male , Melanoma/immunology , Melanoma/pathology , Middle Aged , Skin Neoplasms/immunology , Skin Neoplasms/pathologyABSTRACT
The reduction of nucleic acid by an endogenous polynucleotide phosphorylase and ribonuclease in cells of Brevibacterium JM98A (ATCC 29895) was studied. A simple process was developed for the activation of the endogenous RNA-degrading enzyme(s). RNA degradation was activated by the presence of Pi with 14.2 mumol of ribonucleoside 5'-monophosphate per g of cell mass accumulating extracellularly. The optimum pH for degradation of RNA was 10.5 and the optimum temperature was 55 to 60 degrees C. Enzymatic activity was inhibited by the presence of Ca2+, Zn2+, or Mg2+. Although some of the RNA-degrading enzymatic activity was associated with the ribosomal fraction, most was soluble. Both polynucleotide phosphorylase and ribonuclease activities were identified.