Microbial penetration of gloves following usage in routine dental procedures.

Unsterile polyvinyl, regular latex, and powder-free, modified latex examination gloves were evaluated following usage in routine dental procedures to assess their loss of integrity. Glove fingers were filled with a suspension of red-pigmented Serratia marcescens and drawn across the surface of tryptic soy agar plates. The appearance of red-pigmented Serratia colonies on the plates was used as an indication of glove defects. Unused, unwashed gloves taken at random from boxes served as controls. Of the gloves used in clinical procedures, 83.3% of the polyvinyl gloves, 35.0% of the regular latex gloves, and 7.5% of the powder-free, modified latex gloves allowed penetration of Serratia. Data thus suggest that advances in technology continue to develop a glove with more resistance than regular latex and vinyl gloves to routine clinical usage.     

Development of immunofiltration assay by light addressable potentiometric sensor with genetically biotinylated recombinant antibody for rapid identification of Venezuelan equine encephalitis virus

A genetically biotinylated single chain fragment variable antibody (scFv) against Venezuelan equine encephalitis virus (VEE) was applied in a system consisting of an immunofiltration enzyme assay (IFA) with a light addressable potentiometric sensor (LAPS) for the rapid identification of VEE. The IFA involved formation of an immunocomplex sandwich consisting of VEE, biotinylated antibody, fluoresceinated antibody and streptavidin, capture of the sandwich by filtration on biotinylated membrane, and labeling of the sandwich by anti-fluorescein urease conjugate. The concentration ratio of biotinylated to fluoresceinated antibodies was investigated and optimized. By the IFA/LAPS assay, the limit of detection (LOD) of VEE was approximately 30 ng/ml, similar to that achieved when chemically biotinylated monoclonal antibody (mAb) was applied. Total assay variance of the IFA/LAPS assay for both intra- and inter-assay precision was less than 20%. Assay accuracy was measured by comparing VEE concentrations estimated by IFA/LAPS standard curve to those obtained by conventional protein assay. VEE concentrations were found to differ by no more than 10%. The IFA/LAPS assay sensitivity was approximately equal to that of a conventional enzyme-linked immunosorbent assay (ELISA) utilizing polystyrene plates and a chromogenic substrate; however, less time and effort were required for performance of the IFA/LAPS assay. More importantly, use of genetically biotinylated scFv in the IFA/LAPS assay obviates the need for chemical biotinylation of antibody with resultant possible impairment of the antigen-binding site. Furthermore, the potential for batch-to-batch variability resulting from inequality in the number of biotin molecules labeled per antibody molecule is eliminated.     

Accumulation of filamentous tau in the cerebral cortex of human tau R406W transgenic mice

Missense mutations of the tau gene cause autosomal dominant frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), an illness characterized by progressive personality changes, dementia, and parkinsonism. There is prominent frontotemporal lobe atrophy of the brain accompanied by abundant tau accumulation with neurofibrillary tangles and neuronal cell loss. Using a hamster prion protein gene expression vector, we generated several independent lines of transgenic (Tg) mice expressing the longest form of the human four-repeat tau with the R406W mutation associated with FTDP-17. The TgTauR406W 21807 line showed tau accumulation beginning in the hippocampus and amygdala at 6 months of age, which subsequently spread to the cortices and subcortical areas. The accumulated tau was phosphorylated, ubiquitinated, conformationally changed, argyrophilic, and sarcosyl-insoluble. Activation of GSK-3beta and astrocytic induction of mouse tau were observed. Astrogliosis and microgliosis correlated with prominent tau accumulation. Electron microscopic examination revealed the presence of straight filaments. Behavioral tests showed motor disturbances and progressive acquired memory loss between 10 to 12 months of age. These findings suggested that TgTauR406W mice would be a useful model in the study of frontotemporal dementia and other tauopathies such as Alzheimer's disease (AD).     

Effects of cyclophosphamide on the in vivo response of outbred athymic (nude) mice to a thymus-independent antigen (DNP-AGG-Ficoll).

Both nude mice (nu/nu) and their heterozygous littermates (nu/+) were injected with a single IP dose of 300 mg cyclophosphamide (CY)/kg. CY is a known immunosuppressive agent, which affects primarily B lymphocytes. Immunization with the thymus independent antigen DNP-AGG59-Ficoll after CY treatment disclosed that restoration of the primary direct PFC response occurred more rapidly in nude mice than in nu/+ mice. However in these same experiments, the primary indirect PFC response, recovered earlier in nu/+ mice than in nude mice. After CY treatment, secondary indirect PFC responses were delayed in both nude and nu/+ mice, but the greatest effect was seen in nude mice. The data suggest that the presence of T cells has little if any influence on the recovery capacity of those B cells which are destined to become direct PFC. However the recovery of B cells which are destined to produce indirect PFC responses is facilitated by the presence of T cells.     

Hapten-specific B cell blockade of the immune response to a thymus-independent-1 antigen produced by concomitant administration of a thymus-independent-2 antigen.

CBA/N mice harbour an X-linked B cell defect which is transmitted by CBA/N female mice to their hybrid male progeny. These mice mount normal responses to thymus-dependent (TD) and some thymus-independent (TI-1) antigens, while the response to TI-2 antigens is absent. Hapten-specific plaque-forming cell (PFC) responses to TD antigens can be blockaded by concomitant exposure of these mice to TI-2 antigens bearing the same hapten. This paper investigates in defective mice the blockade of their response to TNP3-LPS (trinitrophenylated lipopolysaccharide, a TI-1 antigen), imposed by DNP59-Ficoll (dinitrophenylated Ficoll, a TI-2 antigen). The effectiveness of the blocking agent, DNP59-Ficoll, differed in various inbred mouse strains: CBA/N X C3H/HeN F1 male greater than CBA/N female greater than CBA/N X C3H/HeN F1 female. The role of T cells in the observed hapten-specific blockade phenomenon was investigated using athymic CBA/N nude mice and a B cell tolerogen. Our findings indicate that T cell participation is not essential for the blockade of CBA/N PFC responses and they suggest that direct blockade of TI- and TD-responsive B cell populations is likely to occur.     

Ultrastructural changes associated with the inhibition of monocyte chemotaxis caused by products of axenically grown Entamoeba histolytica

The supernatant fluid of axenically grown Entamoeba histolytica-HM1 significantly modifies the ultrastructural features associated with monocyte chemotaxis as assayed in Boyden chambers. This morphological evidence supports the existence of a factor, monocyte locomotion inhibitory factor (MLIF), produced by E. histolytica that inhibits the in vitro locomotion of human monocytes. None of the leucocyte-locomotion modifying drugs included in this study (i.e., cytochalasin-B, colchicine, vinblastine, and hydrocortisone) caused changes totally comparable with those induced by MLIF. The most striking feature was the increase of centriole-associated microtubules induced by MLIF and by cytochalasin-B. MLIF may inhibit monocyte locomotion by directly inducing excessive microtubule assembly, although a direct, if somewhat weak effect upon microfilaments cannot be excluded. The increase in microtubules could then represent a perhaps futile attempt of the microtubule organizing center to overcome the locomotion blockade that has occurred elsewhere in the cell. If active in vivo, MLIF may contribute to the paucity of inflammation in the advanced stages of invasive amebiasis, and consequently to the lack of scar tissue formation upon recovery from such lesions, as monocytes constitute an essential link to the healing process.     

Increased multiclonal antibody-forming cell activity in the peripheral blood of patients with SLE

21 patients with criteria for systemic lupus erythematosus (SLE) and 12 normal controls were studied for their spontaneous circulating IgM and IgG plaque-forming cells (PFCs) reactive against sheep erythrocytes (SRBC) and against a panel of five haptens. Quantitatively defined active and mildly active SLE patients had significantly elevated IgM- and IgG-producing PFCs in their peripheral blood reactive with the panel of five chemically defined haptens. Those patients having inactive SLE also showed increased circulating IgM PFCs. Significant elevations in circulating hapten-reactive PFCs were found to correlate progressively with disease activity in the inactive, mildly active, and active SLE patient groups. Circulating IgM- and IgG-secreting PFC reactive against SRBC were both significantly elevated only in those patients with active SLE. The data support the concept that SLE patients have a generalized increase in B cell activity against a broad repertoire of determinants, even those ostensibly unrelated to natural tissue antigens.     

Virology studies and cell lines for prostate cancer

Immunological and biochemical probes for viral genomes and products, growth in cell culture, co-culture methods to activate latent genomes, use of activating agents, and electron microscopy have been used in efforts to demonstrate RNA viruses in prostate cancer. Despite findings of C-type particles and p30 antigens, the role of RNA viruses appears to be secondary, with activation of the virogene being a relatively uncommon occurrence. No compelling evidence for Herpes II or cytomegalovirus as etiologic agents has emerged, despite their common presence in the urogenital tract. Though the search for integration of fragments of viral genome into host DNA is still in progress, it appears unlikely that these viruses would account for a significant number of prostate carcinomas. Progress has been achieved in developing simple, reliable, primary culture methods for human prostatic tissue, using explants or dispersed cells. Three cell lines, all from metastatic foci, have been established, are characterized, and are available for distribution. One neonatal cell strain retains many properties of normal prostate.