The entry of [D-penicillamine2,5]enkephalin into the central nervous system: saturation kinetics and specificity

The delta opioid receptor-selective, enzymatically stable peptide [D-Penicillamine2,5]enkephalin (DPDPE) has recently acquired special significance with the identification of a saturable uptake system for this analgesic into the CNS. The aim of the present study was to characterize further the entry of [3H]DPDPE into the brain and CSF by means of a bilateral in situ brain perfusion method. Initial experiments revealed a saturable [3H]DPDPE uptake into the brain that followed Michaelis-Menten type kinetics with a K(m) value of 45.5 +/- 27.6 microM, a V(max) value of 51.1 +/- 13.2 pmol x min(-1) x g(-1) and a K(d) value of 0.6 +/- 0.3 microl x min(-1) x g(-1). Uptake of [3H]DPDPE into the CSF could not be inhibited (K(d) = 0.9 +/- 0.1 microl x min(-1) x g(-1)). Entry of [3H]DPDPE into the CNS was not inhibited in the presence of 10 mM 2-aminobicyclo-[2,2,1]-heptane-2-carboxylic acid (BCH) or 50 microM ICI 174,864, which suggests that the saturable mechanism does not involve the large neutral amino acid transporter or binding to opioid receptors. It would also appear that [3H]DPDPE is not in competition with either poly-L-lysine or insulin to enter the CNS. However, both of these substances significantly increased the CNS entry of [3H]DPDPE but not that of the vascular space marker [14C]sucrose, and this may have valuable clinical implications. It is not known at present which saturable uptake mechanism is responsible for the CNS entry of [3H]DPDPE, but overall the results suggest a carrier-mediated transport system.     

Comparison of the oral, rectal, and vaginal immunization routes for induction of antibodies in rectal and genital tract secretions of women

To determine which mucosal immunization routes may be optimal for induction of antibodies in the rectum and female genital tract, groups of women were immunized a total of three times either orally, rectally, or vaginally with a cholera vaccine containing killed Vibrio cholerae cells and the recombinant cholera toxin B (CTB) subunit. Systemic and mucosal antibody responses were assessed at 2-week intervals by quantitation of CTB-specific antibodies in serum and in secretions collected directly from mucosal surfaces of the oral cavity, rectum, cervix, and vagina with absorbent wicks. The three immunization routes increased levels of specific immunoglobulin G (IgG) in serum and specific IgA in saliva to similar extents. Rectal immunization was superior to other routes for inducing high levels of specific IgA and IgG in rectal secretions but was least effective for generating antibodies in female genital tract secretions. Only vaginal immunization significantly increased both specific IgA and specific IgG in both the cervix and the vagina. In addition, local production of CTB-specific IgG in the genital tract could be demonstrated only in vaginally immunized women. Vaginal immunization did not generate antibodies in the rectum, however. Thus, generation of optimal immune responses to sexually transmitted organisms in both the rectal and the genital mucosae of women may require local immunization at both of these sites.     

Immunologic mechanisms in common rheumatologic diseases

Rheumatoid arthritis and seronegative spondyloarthropathies are rheumatologic diseases that likely are caused by inflammatory reactions occurring in genetically predisposed individuals mounting an immune response to the antigen. Understanding the immunopathology of these diseases provides insight into their etiology, pathogenesis, and a rationale for therapies targeting immune component interactions. Although the antigen in rheumatoid arthritis is not known, several bacterial antigens have been associated with seronegative spondyloarthropathies. These antigens result in an interaction between the human leukocyte antigen-B27 restricted CD8 positive T lymphocytes and the antigen presenting cell, producing an inflammatory response. Rheumatoid factors are autoantibodies directed against the fragment crystallizable portion of the immunoglobulin G. Rheumatoid factor immunoglobulin G immune complexes contribute to the inflammatory events in the rheumatoid joint, and may play an important role in antigen presentation. A novel antigen capture enzyme linked immunosorbent assay was developed that mimicked B cell surface expressed rheumatoid factor. Conversely, a direct binding enzyme linked immunosorbent assay mimicked secreted rheumatoid factor. Comparison of rheumatoid binding enzyme linked immunosorbent assays showed that the physical state of rheumatoid factor can affect binding characteristics. The state of glycosylation of immunoglobulin G may contribute to its antigenic structure. These physical characteristics may be important in rheumatoid factor's pathogenic role in rheumatoid arthritis.     

Role for macrophage inflammatory protein-2 in lipopolysaccharide-induced lung injury in rats

Macrophage inflammatory protein-2 (MIP-2) is a C-X-C chemokine that possesses chemotactic activity for neutrophils. Rat MIP-2 was cloned and expressed as a 7.9-kDa peptide that exhibited dose-dependent neutrophil chemotactic activity at concentrations from 10 to 250 nM. Rabbit polyclonal Ab to the 7.9-kDa peptide showed reactivity by western blot analysis and suppressed its in vitro chemotactic activity. Cross-desensitization chemotaxis experiments suggested that the chemotactic responses elicited by MIP-2 and the related chemokine, cytokine-induced neutrophil chemoattractant, may be mediated through a common receptor. Also, chemotactic responses to human GRO-alpha were blocked by exposure of human neutrophils to either GRO-alpha or rat MIP-2, suggesting conservation of this receptor-mediated response. After LPS instillation into rat lung, mRNA for MIP-2 was up-regulated in a time-dependent manner, peaking at 6 h. MIP-2 protein was detected in bronchoalveolar lavage fluids of these animals and a significant amount of chemotactic activity present in these fluids was attributed to MIP-2. On the basis of intrapulmonary instillation of Ab to MIP-2, neutrophil accumulation in lungs after airway instillation of LPS was found to be MIP-2-dependent. These data indicate that MIP-2 plays a significant role in LPS-induced inflammatory response in rat lungs and is required for the full recruitment of neutrophils.     

Persistent papillomavirus infection in a cat

The purpose of this study was to further define the cellular response to titanium and polymethylmethacrylate (PMMA) particles in aseptic loosening, and to determine if the use of pamidronate may be effective in inhibiting bone resorption associated with this response. Macrophages and osteoblasts were cocultured to simulate the environment around an aseptically loose prosthesis. Macrophages were plated on the bottom of six well plates and osteoblasts were plated on culture dish inserts, and placed into the wells with the macrophages. Incubation of macrophages with PMMA in this system led to release of prostaglandin E (PGE2), granulocyte macrophage-colony stimulating factor (GM-CSF), and interleukin-6 (IL-6). Incubation with titanium led to release of tumor necrosis factor (TNF) and IL-6. Exposure of calvaria to media from cells exposed to either PMMA or titanium led to release of calcium 45. Incubation of calvaria with pamidronate was able to inhibit release of calcium 45 associated with exposure to the macrophage/osteoblast/particle conditioned medium. Bone resorption at the interface between implant and bone is a consistent feature leading to loosening of orthopedic implants. By inhibiting bone resorption associated with the inflammatory response to implant particulates, pamidronate or other bisphosphonates may have clinical utility in the treatment or prevention or aseptic loosening.     

Pentachlorophenol accumulation in the freshwater mussels Anodonta anatina and Pseudanodonta complanata, and some physiological consequences of laboratory maintenance

Freshwater mussels Anodanta anatina and Pseudanodonta complanata were exposed to (14C)-pentachlorophenol. The wet weight based bioconcentration factor (BCF = activity in animal per activity in water) at steady state varied from 80 to 120 for A. anatina and from 61 to 85 for P. complanata. The species did not differ significantly in their wet weight or lipid based BCFs but dry weight based values were significantly higher (40-50%) for A. anatina. The soft tissue dry weight and dry weight based condition index of A. anatina (Cl4 = soft tissue dry weight per shell length) differed significantly between natural mussel populations. In animals kept from 4 to 8 months in laboratory conditions, the soft tissue dry weight and glycogen content decreased more rapidly when mussels were maintained at 15 than at 5 degrees C. However, glycogen content in the digestive gland or adductor muscle did not differ in mussels maintained in the laboratory (5 degrees C) when compared to the natural population. The adductor muscle protein content differed between laboratory maintained animals and the natural population in Lake H?yti?nen but there was no difference in the soft tissue lipid content. Trace metal concentrations and calcium in the soft tissue were in general higher in laboratory maintained mussels. In addition, laboratory maintenance affected the reproductive cycle of A. anatina.