Infant and preschool immunization delivery in Alberta and Ontario: a partial cost-minimization analysis

This paper is a partial cost-minimization analysis of preschool immunization delivery in Alberta and Ontario. Public health nurses deliver such immunization in Alberta while in Ontario it is usually provided by private physicians. In constant 1986 dollars, labour costs were 2.9 times higher in Ontario than in Alberta. Alberta and Ontario achieved equal success in preventing diphtheria, tetanus and poliomyelitis in the target population of zero to four years of age. Ontario's pertussis rates were higher than Alberta's from 1980 to 1986 inclusive (p less than 0.01). Rubella rates were higher in Alberta from 1980 to 1986 inclusive (p less than 0.05) but the congenital rubella rates for the same period were not. During 1980, Ontario's measles rate was higher (p less than 0.01) while for 1982 and 1986, Alberta's measles rates were higher. In 1986, Alberta's mumps rate was higher than Ontario's (p less than 0.01). The findings argue in favour of the less costly public health nurse approach to immunization delivery. A more definitive conclusion could have been reached had the provinces maintained more detailed age-specific disease incidence data.     

Layer-by-layer coating of degradable microgels for pulsed drug delivery.

Recently, we reported on "self-rupturing" microcapsules which consist of a biodegradable dextran-based microgel surrounded by a polyelectrolyte membrane. Degradation of the microgel increases the swelling pressure in the microcapsules which, when sufficiently high, ruptures the surrounding polyelectrolyte membrane. The membrane surrounding the microgels is deposited using the layer-by-layer (LbL) technique, which is based on the alternate adsorption of oppositely charged polyelectrolytes onto a charged substrate. In this paper, we characterize with confocal microscopy, electrophoretic mobility, scanning electron microscopy and atomic force microscopy in detail the deposition and the properties of the LbL coatings on the dextran microgels. We show that by fine-tuning the properties of both the microgel core and the LbL membrane the swelling pressure which is evoked by the degradation of the microgel is indeed able to rupture the surrounding LbL membrane. Further, we show that the application of an LbL coating on the surface of the microgels dramatically lowers the burst release from the microcapsules and results in massive release at the time the microcapsules rupture.     

In vivo comparison of MR phase distribution and 1/T2* with morphologic parameters in the distal radius

A new approach based on the calculation of the phase variance in a region of interest on the phase images of a simple gradient echo sequence, was used to assess the properties of trabecular bone in the distal radius. The phase variance reflects the distribution of field inhomogeneities due to the difference in magnetic susceptibility between bone and marrow in a way similar to T2*. However, the phase variance monitors the intervoxular differences, whereas T2* studies the intravoxular inhomogeneities. In this study of the radius of seven volunteers, both techniques were compared with parameters characterizing trabecular bone structure derived from high resolution MR images. Parameters such as the apparent bone area fraction, trabecular number, thickness and spacing, and box-counting fractal dimension were determined.     

Einzelreferate und Buchbesprechungen

Ohne Zusammenfassung     

Indoleamine 2,3-dioxygenase, tryptophan catabolism, and Mycobacterium avium subsp. paratuberculosis: a model for chronic mycobacterial infections

Virulent mycobacterial infections progress slowly, with a latent period that leads to clinical disease in a proportion of cases. Mycobacterium avium subsp. paratuberculosis is an intracellular pathogen that causes paratuberculosis or Johne's disease (JD), a chronic intestinal disease of ruminants. Indoleamine 2,3-dioxygenase (IDO), an enzyme that regulates tryptophan metabolism, was originally reported to have a role in intracellular pathogen killing and has since been shown to have an important immunoregulatory role in chronic immune diseases. Here we demonstrate an association between increased IDO levels and progression to clinical mycobacterial disease in a natural host, characterizing gene expression, protein localization, and functional effects. IDO mRNA levels were significantly increased in M. avium subsp. paratuberculosis-infected monocytic cells. Levels of both IDO gene and protein expression were significantly upregulated within the affected tissues of sheep with JD, particularly at the site of primary infection, the ileum, of animals with severe multibacillary disease. Lesion severity was correlated with the level of IDO gene expression. IDO gene expression was also increased in the peripheral blood cells of M. avium subsp. paratuberculosis-exposed sheep and cattle. IDO breaks down tryptophan, and systemic increases were functional, as shown by decreased plasma tryptophan levels, which correlated with the onset of clinical signs, a stage well known to be associated with Th1 immunosuppression. IDO may be involved in downregulating immune responses to M. avium subsp. paratuberculosis and other virulent mycobacteria, which may be an example of the pathogen harnessing host immunoregulatory pathways to aid survival. These findings raise new questions about the host-mycobacterium interactions in the progression from latent to clinical disease.     

A method for identifying megakaryocytic and erythroid cells by a combined immunocytochemical and cytochemical stain.

The effectiveness of immunoperoxidase staining for platelet glycoprotein IIb/IIIa coupled with cytochemical staining for hemoglobin has been evaluated as a dual staining technique for identifying lineage-specific characteristics of the megakaryocytic and erythroid series in cells of the same hemopoietic tissue preparation. A sequence of staining was established which produced a circumferential brown stain around cells of the megakaryocytic series, and a diffuse yellow to orange stain in the cytoplasm of cells of the erythroid series. Each staining reaction possessed a high degree of specificity and sensitivity which enabled the combined stain to provide a convenient means for establishing the megakaryocytic and erythroid nature of individual cells in hematological specimens where classification cannot be achieved with certainty on morphological grounds.