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H M Hallgren

Publications and source records attributed to H M Hallgren.

24 records · Page 2Linked to original sources
PubMedDate not supplied

Effects of preliminary culture on the membrane microviscosity of lymphocytes from young and old donors. Microviscosity correlates with mitogenic response.

Membrane microviscosity was assessed by a fluorescence polarization technique in fresh and precultured human peripheral blood lymphocytes of young and old subjects. Membrane microviscosity was significantly higher in fresh, non-treated cells of old donors as compared to young adults. Preincubation of cells in culture medium supplemented with pooled human serum diminishes the original microviscosity difference between the age groups. The observed increase in membrane fluidity correlates with the improvement of the mitogen-induced proliferative response due to preculturing cells from aged subjects. The results support the suggestion that membrane microviscosity can affect the proliferative response of lymphocytes, and it may play a role in the decline of the immune responsiveness in the elderly.

Journal Article↗
PubMedDate not supplied

Aging and lymphocyte function: a model for testing gerontologic hypotheses of aging in man.

Advanced age in humans and experimental animal models has been consistently associated with declines in the in vivo and in vitro responsiveness of T lymphocytes. The declines in vitro responses cannot be explained by decrease in numbers of differentiated T cells or by age-associated changes in the proportion of CD4+ 'helper' to CD8+ 'cytotoxic/suppressor' T cells. However, recent studies have demonstrated a decline with age in numbers of what appear to be antigenically 'naive' or 'virgin' T cells, accompanied by a proportionate increase in 'memory' T cells which mediate anemnestic or recall responses to previously encountered antigens. The findings lead to the hypothesis that thymic involution leads to decline in input of newly differentiated 'naive' T cells, while T cell number in peripheral tissues is maintained by accumulation of longer lived 'memory' T cells due to lifetime antigen exposure. So far, limited data suggest that increasing average biological age of the memory T cells which accumulate with age is largely responsible for declines in vitro activation responses of human peripheral blood T cells and that a subset of these memory T cells becomes refractory to activation stimuli as a consequence of in vivo cellular aging. Approaches to testing this hypothesis are presented and the implications of these findings for use of memory T cells as a model for investigating the mechanisms of in vivo cellular aging, are discussed.

Journal Article↗
PubMedDate not supplied

Histocompatibility determinants in idiopathic scoliosis.

The HLA antigen distribution in 64 random scoliosis patients has been determined. Of the surgical group (greater than 50 degrees), the specificity W19 was increased. In the nonsurgical group (less than 45 degrees) the W19 specificity was also increased; however, the only specificity significantly increased was A29 (X2=11.64, P=less than .02). These observations are preliminary and more extensive work is needed to establish the relevance of the major histocompatibility system in the etiology and progression of idiopathic scoliosis.

Adolescent↗