Intradermal immunization of rats with plasmid DNA encoding Schistosoma mansoni 28 kDa glutathione S-transferase

Direct administration of plasmid DNA encoding an antigen represents an attractive approach to vaccination against infectious diseases, particularly in developing countries where easy-to-handle and cost-effective vaccines are needed. We have investigated the potential of DNA immunization to induce a specific antibody response against Schistosoma mansoni , using plasmid-DNA encoding the protective antigen, S. mansoni 28 kDa glutathione S-transferase (Sm28GST). Since S. mansoni parasite penetrates into its host through the skin, this tissue was chosen for plasmid DNA delivery. Following plasmid DNA administration into the skin of rats, the parasite antigen was detected in skin cells by immunohistochemistry. Three administrations of 200 μg plasmid at 14 day intervals led to the induction of a long-lasting specific IgG antibody response in the sera of immunized rats, with a predominance of IgG2a and IgG2b subclasses. Sera of immunized animals were able to mediate antibody-dependent cellular cytotoxicity in vitro , leading to the specific killing of parasite larvae. A parasite challenge performed on plasmid DNA-immunized animals induced a strong and rapid boosting effect on the specific IgG antibody response. These results demonstrate the potential of genetic immunization via the skin with plasmid DNA encoding Sm28GST for inducing immune responses with protective patterns against an S. mansoni infection .     

In situ immunological characterization of the infiltrating cells in positive patch tests

Skin biopsies from positive allergic patch tests were analysed by immunoenzymatic labelling of frozen sections with monoclonal antibodies. In seventeen patients the cellular infiltrate consisted of T cells admixed with Langerhans cells/indeterminate cells, but in two patients there were also many B lymphocytes. The B cells were accompanied by dendritic reticulum cells forming B-cell follicles, indistinguishable from those of normal and hyperplastic lymph nodes. There was no correlation between these two immunohistological staining patterns and the sensitizing antigen, the extent of local reaction or the time from epicutaneous application of allergen to examination (2 to 16 days). The ratio between T-helper and T-suppressor cells varied considerably, and showed no correlation with these variables. In all patients the infiltrating T cells expressed HLA-DR antigen. Transferrin receptors were identified on the infiltrating T cells in biopsies from nine patients. These data indicate activation of T cells in the infiltrate from positive patch tests, and support the functional significance of Langerhans cells in the initiation and maintenance of cutaneous contact allergy. An involvement of B cells and B-cell accessory cells in the pathogenesis of contact allergic reactions is also suggested. The presence of dendritic reticulum cells in skin infiltrates from positive patch tests may reflect a functional implication of the skin in the development of B-cell memory.     

Long-term Effectiveness of Probation, Short-term Intervention and LAI Administration for Reducing DUI Recidivism

Driving under the influence of alcohol (DUI) arrest records were checked for subjects participating in the Mississippi DUI Probation Follow-up project 6 to 9 years after project entry. The efficacy of short-term intervention, probation, and Life Activities Inventory (LAI) administration for reducing long-term DUI recidivism were evaluated using a logit analysis. A small but statistically significant effect of probation for reducing long-term recidivism was found for offenders classified both as low-risk and high-risk drinkers. However, an interaction effect of combining probation with short-term intervention, which was suggested by an earlier 2-year recidivism analysis, was not statistically significant after the longer tracking period. Administration of the LAI questionnaire was found to reduce recidivism only for offenders classified as low-risk, replicating findings after 2 years of recidivism tracking.     

Clonal evolution in cutaneous malignant histiocytosis

A 56–year-old woman is reported with malignant histiocytosis which for 17 months was confined to the skin but eventually involved lymph nodes, blood and bone marrow. Using DN'A measurements by flow cytometry a clonal evolution from an abnormal hyperdiploid to a hypotetraploid cell clone took place when the patient went from the cutaneous to the disseminated phase of the disease. Thus DNA measurements upon tumours may predict the transition from the cutaneous to the disseminated stage.     

Expression of a cell adhesion protein (VLA β) in normal and diseased skin

Biopsies from normal skin (n = 17) and various cutaneous disorders (n = 83) were examined immunohistologically for reactivity with an antibody (CD29) against the common beta chain of the VLA integrin family. In normal skin, CD29 recognized a number of cell types, i.e. endothelial cells, fibroblasts, T lymphocytes and basal keratinocytes. Similar cells were positive in diseased skin, but the expression of VLA beta was upregulated on keratinocytes. The phenotype of the VLA beta-positive T cells was examined in more detail by staining with anti-T-cell antibodies, i.e. CD3, CD4, CD8, CD45RO (UCHL1) and CD45R (2H4). These studies showed that most of the T cells in normal skin, benign cutaneous conditions and early cutaneous T-cell lymphomas (CTCL) expressed a similar phenotype and resembled antigen committed 'memory' (helper/inducer) cells (CD4+, CD29+, CD45RO+, CD45R-). In advanced CTCL, expression of these antigens was more variable, and many of these infiltrates showed aberrant (or unusual) expression of CD29, CD45RO, CD45R and other T-cell antigens. It is concluded that several cells involved in cutaneous immune reactions express a molecule (VLA beta) which acts as a receptor for extracellular matrix components. This molecule is important for the attachment of cells to connective tissue constituents and may act to facilitate the migration of lymphocytes (and other cells) during immune reactions in normal and diseased cutaneous conditions. Advanced CTCL differ from the early lesions and it is possible that there is a progressive accumulation of increasingly malignant (or transformed) cells in these conditions.     

Endothelial Cell Lining of Bioprosthetic Heart Valve Material

In this in vitro study, the growth properties of cultured endothelial cells on conventionally treated pericardial valve material were measured. These data were compared to endothelial cell proliferation on an alternatively treated valve material. This alternative preservation procedure was developed in order to bind free, residual glutaraldehyde in the valve tissue by reaction with L-glutamic acid. In order to optimize endothelial cell attachment and proliferation, fibronectin and fibrillar collagen type I were tested as surface precoating substances. Cell viability of the seeded cells was evaluated by means of proliferation kinetics, antithrombotic activity, and morphological appearance. Endothelial cell death occurred within the first 2 days after seeding on conventionally treated valve tissue, independent of the type of precoating. On alternatively treated tissue, regular endothelial cell proliferation was observed. Precoating with fibrillar collagen markedly increased endothelial cell attachment and proliferation as compared to fibronectin. Maintenance of antithrombotic activity of the seeded cells was proven by regular release of prostacyclin.     

SKELETAL MUSCLE PROTEASE ACTIVITIES ARE UNALTERED IN CIRRHOTIC RATS BUT ALTERED IN RESPONSE TO ETHANOL AND ACETALDEHYDE IN VITRO

This study was carried out in an attempt to differentiate betweenthe contribution of liver impairment and direct actions of alcoholin myopathy of alcoholic liver disease. Using an animal modelof cirrhosis we have previously shown that protein syntheticpotential in muscle was not significantly altered. We thereforeinvestigated the possibility that muscle degradation is increased.Cirrhosis was induced by carbon tetrachloride gavage in malerats receiving phenobarbitone in their drinking water. Controlswere given phenobarbitone alone. After 135 days the free, latentand total activities of the lysosomal enzymes cathepsin B andcathepsin D in gastrocnemius muscle were unaffected by the inductionof experimental cirrhosis when expressed relative to tissuewet weight, protein or DNA. The non-lysosomal enzyme neutralprotease was also measured in gastrocnemius muscle from controland cirrhotic rats. There was no difference between the twogroups in the free, latent or total activities. Addition ofethanol and acetaldehyde to the assay mixtures in some casessignificantly altered the relative activities of the proteasesin latent and free compartments of the cirrhotic tissues. Incontrol tissues a different pattern of response emerged. Itis concluded that in cirrhosis, at least in the carbon tetrachloride-inducedrat model, there is no change of the activity of cathepsin Band D and the neutral protease activity in gastrocnemius. Smallbut significant effects of ethanol and its metabolite acetaldehydeon latent and free muscle protease activity were demonstrated.     

Noradrenaline-phospholipid interactions

The uptake of (±)-[³H]noradrenaline from an aqueous phase to an ether phase containing dissolved lecithin has been measured. No differences between the behaviour of (+)- or (—)-noradrenaline in this system could be detected. The biological implications of this finding are discussed.