Acanthocheilonema viteae: stage-specific expression of G-protein alpha-subunits.

We have previously demonstrated by Western blot analysis that the adult stage of the filarial nematode Acanthocheilonema viteae expresses the alpha-subunits of heterotrimeric G-proteins corresponding to GS and Gq. We now show, using the same technique, that these two alpha-subunits are not detectable in the microfilaria stage of the parasite. Conversely, microfilariae contain Go, an alpha-subunit not expressed by the adult worm. No other G-protein alpha-subunits were found in microfilariae by Western blotting. However, reverse transcriptase-polymerase chain reaction (RT-PCR) with degenerate G-protein oligonucleotide primers, followed by hybridisation analysis, using oligonucleotides specific for individual G-protein alpha-subunits, not only confirmed expression of Go, but also detected Gi1 and G11 alpha-subunits. G-protein expression in infective larvae was also investigated by RT-PCR analysis: this stage of the organism was found to resemble the adult more than the microfilaria but differed from the adult in that GS was absent and Gi3 was present. The significance of these stage-specific differences in G-protein expression is discussed with respect to their possible role in parasite development and survival.

Differential G-protein expression during B- and T-cell development.

The molecular mechanisms underlying B- and T-cell development are, as yet, poorly understood. However, as G proteins regulate a diverse range of biological responses including growth, proliferation and differentiation, we have investigated differential expression of G proteins during B- and T-cell development with the aim of identifying key signals involved in lymphocyte maturation. Differential expression of beta 1/2 and alpha-subunits of the Gs-, i- and q-families was found throughout lymphoid development. Most strikingly, G alpha i1 and G alpha i1 were very weakly, or not expressed in pre-, immature and mature B cells, thymocytes or mature T cells, but strongly induced in mature B-lymphoblastoid cell lines, some of which have been used as models of germinal centre B cells, suggesting that expression of these G proteins may correlate with the later stages of B-cell development. In contrast, G alpha 16 expression was highest in T cells and pre-B cells and progressively declined with B-cell maturation. These findings suggest that G proteins, and the signals they regulate, such as ion channels and/or adenylate cyclase (G alpha s/i) and phospholipase C (G beta gamma and G alpha 11/16) are differentially regulated in lymphoid cells in a maturation-and lineage-dependent manner.

Characterization of heterotrimeric G-proteins in adult Acanthocheilonema viteae.

Heterotrimeric G-proteins have been found in eukaryotic cells, from yeast to humans, but have received little attention, to date, with respect to parasitic organisms. We now present the first report of the characterization of heterotrimeric G-proteins expressed in a filarial nematode, Acanthocheilonema viteae. Using a combination of (i) affinity labelling with [alpha-32P]GTP; (ii) ADP-ribosylation with cholera toxin and pertussis toxin; (iii) Western blotting with a panel of anti-G-protein antibodies; and (iv) reverse transcriptase-PCR with degenerate G-protein oligonucleotide primers followed by hybridization analysis using oligonucleotides specific for individual G-protein subunits, we demonstrate that adult A. viteae expresses homologues of the beta 1- and/or beta 2-like subunits and alpha-subunits of the Gs, G1, Gq and G12 subfamilies found in mammals. The role which these G-proteins may play in the biology of the organism is discussed.

Gender differences in health related behaviour: some unanswered questions.

To date, no single explanation has accounted for discrepancies between male and female morbidity rates and health care utilization patterns. The sociomedical approach to sex/gender differences in health related behaviour has generated a variety of hypotheses. However, despite extensive study, many unanswered questions remain. The findings of this study fall short of offering conclusive evidence as to the causes of variations in morbidity and health services use between women and men. However, an effort is made to identify the salience of social role and related social status characteristics (e.g. labour force participation) in accounting for variation in health, illness and sick role behaviour. This paper utilizes data from the 1983 Winnipeg Area Study. Findings of this study raise questions about the adequacy of current concepts and measures for studying sex/gender differences in health related behaviour. The study concludes with a critical discussion of conceptual, methodological and theoretical issues which must be considered in our efforts to advance our understanding of why women experience greater longevity, but experience greater morbidity and make more extensive use of health services.

What is reasonable is true. Life satisfaction and functional disability among day hospital participants.

Among the several kinds of health care programs enabling the elderly to maintain community residence is the geriatric day hospital. An investigation was undertaken, utilizing structured interviews, to determine what factors influenced life satisfaction and functional disability among the elderly attending three day hospitals in Winnipeg, Canada. Findings indicate that the major predictors of functional disability include perceived health, Canadian ethnicity and differential services. Those for life satisfaction (activity, socio-economic status and health) were similar to those cited for elderly generally in the population.