Possibilities for the analysis of peripheral blood B cell subpopulations in a routine immunological laboratory.

B cells play a vital role in the defence of the body against infectious agents. Apart from their ability to present antigen to T cells, B cells are mainly producers of antibodies. These play a crucial role in the effective elimination of infection and are also involved in the regulation of the immune response. The analysis of peripheral blood B cell subpopulations that makes it possible to monitor the development of B cells to the stage of antibody producing plasmablasts provides a valuable laboratory parameter which is important for both the study of the pathogenesis and diagnosis of some diseases. Laboratory analysis of B cell subpopulations is now a routinely available laboratory option thanks to the development of multicolour flow cytometry. This article summarizes the core knowledge which is currently applied to the analysis of B cell subpopulations in immunological laboratories.

Fate of 3H-thymidine labelled myogenic cells in regeneration of muscle isografts.

Intact and denervated extensor digitorum longus (EDL) muscles of 20-day-old inbred Lewis-Wistar rats were labelled with 3H-thymidine. Ninety minutes after the injection of the isotope 4.0% of the nuclei were labelled in the intact (i.e. innervated) and 9.6% in the muscles, denervated 3 days before administration of the isotope. The labelled EDL muscles were grafted into the bed of the previously removed EDL muscles of inbred animals and these isografts were studied 30 days later. In the EDL muscles, regenerated from innervated isografts only occasionally labelled endothelial cells were found whereas in the muscles regenerated from denervated isografts also parenchymal muscle nuclei were regularly labelled. The incidence of labelled nuclei in the regenerated EDL muscles was, however, about 20 times lower than in the donor EDL muscles. The presen experiments provide a direct proof of utilization of donor satelite cell nuclei for regeneration in grafted muscle tissue. With respect to the low incidence of labelled nuclei in regenerated EDL muscles, other sources of cells apparently also contribute to the regeneration process.

Different changes in contractile and histochemical properties of reinnervated and regenerated slow soleus muslces of the guinea-pig.

The changes in contraction time (CT) and histochemical muscle fibre pattern are compared with respect to ATPase activity of the slow soleus muscle of the guniea-pig during regeneration in free grafts and reinnervation after nerve interruption. Interruption of the nerve by crushing at birth results first in prolongation of CT which later returns to normal (control) values. A homogeneous fibre pattern is established related to the homogeneity of the motor units constituting the muscle. In the regenerating muscle CT and muscle fibre pattern of the graft repeat the changes during postnatal development, i.e. CT shows progressive prolongation accompanied by transformation of a heterogeneous (fibres of high and low ATPase activity) to a homogeneous (fibres of low activity only) fibre pattern. However, the regenerating muscle also shows an initial phase with slow CT. Thus the changes in reinnervation and regeneration of the muscle after birth differ, the reinnervated muscle revealing only prolongation, the regenerated muscle a temporary shortening followed by prolongation, i.e. a biphasic development of CT.

Effect of exercise on muscle fibre composition and enzyme activities of skeletal muscles in young rats.

Young Wistar rats underwent dynamic (D) or static (S) exercise from the 5th to 35th day after birth. Histochemical and biochemical analysis were performed in the extensor digitorum longus (EDL) and the soleus muscle (SOL). Lactate dehydrogenase (LDH) (regulating anaerobic metabolism) and citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase (HAD) (both regulating aerobic metabolism) activities were determined spectrophotometrically. An increase of the fast oxidative-glycolytic (FOG) muscle fibres was found in the slow SOL muscle in both trained groups, i.e. by 10% in group D and by 7% in group S in comparison with the C group. The EDL muscle fibre distribution did not differ from those of control animals in respect to the slow oxidative (SO) fibre type. A higher percentage of FOG fibres by 19% was found in group D contrary to a decreased number of the fast glycolytic (FG) muscle fibres in this trained group. The greatest increase of CS (EDL 185%, SOL 176%) and HAD (EDL 83%, SOL 178%) activities were found in group D as compared with control group (C). Only small differences were observed in LDH activity. The values of characteristic enzyme activity ratios show that dynamic training resulted in an elevation of oxidative capacity of skeletal muscle, while the static load led preferentially along the glycolytic pathway. It may be concluded that an adaptive response to the training load during early postnatal development is different due to the type of exercise (dynamic or static) and/or the type of skeletal muscle (fast or slow).