Fractionation of mouse T and B lymphocytes by preparative cell electrophoresis. Efficiency of the method

Mouse lymphocytes have been fractionated in preparative cell electrophoresis into two functionally viable populations, a high mobility cell (HMC) and a low mobility cell (LMC) population. The distribution of HMC in CBA spleen, blood, and lymph node corresponds to known proportions of θ-positive cells in these organs. The HMC carry the θ-isoantigen, respond to phytohemagglutinin in vitro, and induce a graft-versus-host reaction in newborn F₁ hybrid mice. Nearly all spleen LMC have complement receptors on their surface. About 70% of spleen LMC are sensitive to anti-MBLA serum and form “caps” when incubated with FITC-conjugated anti-Ig. Only LMC respond to E. coli lipopolysaccharide. Thus, T cells localize in the HMC population and B cells in the LMC population. There is no detectable contamination of T lymphocytes among the LMC, nor of B lymphocytes among the HMC.     

Species richness of Macrolepidoptera on Finnish deciduous trees and shrubs

Summary Species richness of Macrolepidoptera on Finnish trees and shrubs was analysed by means of stepwise regression analysis. The explaining variables were plant frequency, geographical range, plant height, number of relatives and leaf size.Total frequency of the host plant, which correlated strongly with range, explained 57% of the observed variance of lepidopteran species richness on deciduous trees and shrubs. Height of plant and number of relatives explained significantly the residual variation and altogether these three variables explained 71% of the variance of species richness.Analyses at the plant genus level gave similar results and frequency, height and number of relatives explained 78% of the variance of species richness of Macrolepidoptera on deciduous plant genera.When conifers were included in the analysis leaf size also becomes a significant variable. Leaf size can, however, act as a dummy variable which effectively distinguishes conifers from deciduous trees.The validity of different models explaining herbivore species richness on plants is discussed. The results of this study favoured more than earlier studies the importance of relatedness of host plants as a factor which determines the species richness of herbivores.     

Bioluminescent assay of D-3-hydroxybutyrate in serum

An enzymatic assay of D -3-hydroxybutyrate in which the hydroxybutyrate dehydrogenase reaction is coupled to the bacterial oxidoreductase—uciferase system is described. The bioluminescent assay is based on either, end-point, or on initial velocity measurements. This simple and rapid assay requires a single serum sample of 10 μl. Its linear range covers two orders of magnitude from 10^?6 mol/I upwards. This assay is suitable for the routine determination of D -3-hydroxybutyrate in human blood with good accuracy.     

Expression of the major AgB histocompatibility complex antigens on different structural components of rat kidney and heart

We have analyzed the expression of the major AgB locus antigens on the parenchymal cell components of rat kidney and heart using (a) heterologous antisera raised against isolated molecules and (b) conventional alloantisera, directed to the serologically detectable AgB and Ia allodeterminants. A modified Staphylococcus aureus Cowan I rosette assay, enabling the characterization of the rosette-forming cell type from stained cytocentrifuged cell smears, was used. The AgB and Ia antigens were detected by both types of antisera on the “passenger” cells of either organ: the anti-Ia reacted especially strongly with a fraction of “passenger” lymphocytes, and anti-AgB also with the “passenger” erythrocytes. All kidney parenchymal components were nearly devoid of both AgB and Ia antigens: only a weak reaction was observed with the vascular endothelial, tubular, or glomerular cells after treatment of either type of antiserum. The heart endothelial cells expressed the AgB and probably some Ia: an intermediary intensive reaction was observed after treatment with heterologous or allospecific anti-AgB, and a weak reaction with anti-Ia. The heart myocardial muscle cells, on the other hand, were nearly devoid of both antigens: no reactivity with heterologous anti-Ia and only a marginal reactivity with heterologous or allospecific anti-AgB was observed.     

Stand edge effects on distribution and condition of Diprionid sawflies

1 We investigated stand edge effects on Diprion pini cocoon condition and distribution after an outbreak of unprecedented magnitude in Finland. We hypothesized that forest fragmentation and the resulting proportional increase in stand edge habitats may have led to the increase in outbreak area: D. pini may profit from edge habitats and so escape its control mechanisms more easily. This hypothesis was based on the observation that no outbreak occurred in neighbouring Russian Karelia, where the proportion of edge habitats between different stand types and/or successional stages is significantly less than in Finland. 2 To test the hypothesis, we determined the amount and condition of cocoons in an outbreak area, along transects going from stand centres through edge habitats, towards neighbouring stand centres. 3 Both the total number and number of cocoons in different conditions varied significantly between edges and centres. The effects were more pronounced when age difference between neighbouring stands increased. 4 Edge habitats did not benefit D. pini. Both the total number and number of hatched cocoons were consistently higher in centre than in edge habitats. 5 Defoliation was unrelated to distance from the edge, even on transects where cocoon density and condition was correlated to distance from the edge. 6 We conclude that edge habitats have an inhibitive effect on D. pini densities, and therefore our original hypothesis was rejected. The importance of small mammals to D. pini mortality was demonstrated, and we suggest further investigation of this predator–prey relationship because of its potential for limiting outbreak risk and/or damage through silvicultural measures.     

Green islands — predation not nutrition

Summary The existence of green islands around wood-ant nests in otherwise damaged birch forests has been explained by two alternative hypotheses: (1) predation by ants protects the trees against defoliators, and (2) the ants ameliorate tree vigor by concentrating soil nutrients. The size of green islands and the nitrogen content of the soil and foliage do not support the nutrition hypothesis. These data and general knowledge about the foraging strategy of wood ants are consistent with the predation hypothesis.     

Neuromuscular training and the risk of leg injuries in female floorball players: cluster randomised controlled study

Objective To investigate whether a neuromuscular training programme is effective in preventing non-contact leg injuries in female floorball players.Design Cluster randomised controlled study.Setting 28 top level female floorball teams in Finland.Participants 457 players (mean age 24 years)—256 (14 teams) in the intervention group and 201 (14 teams) in the control group—followedup for one league season (six months).Intervention A neuromuscular training programme to enhance players’ motor skills and body control, as well as to activate and prepare their neuromuscular system for sports specific manoeuvres.Main outcome measure Acute non-contact injuries of the legs.Results During the season, 72 acute non-contact leg injuries occurred, 20 in the intervention group and 52 in the control group. The injury incidence per 1000 hours playing and practise in the intervention group was 0.65 (95% confidence interval 0.37 to 1.13) and in the control group was 2.08 (1.58 to 2.72). The risk of non-contact leg injury was 66% lower (adjusted incidence rate ratio 0.34, 95% confidence interval 0.20 to 0.57) in the intervention group.Conclusion A neuromuscular training programme was effective in preventing acute non-contact injuries of the legs in female floorball players. Neuromuscular training can be recommended in the weekly training of these athletes.Trial registration Current Controlled Trials ISRCTN26550281.