In situ effector pathways of allograft destruction. 2. Generation of the "humoral" response in the graft and the graft recipient

The frequency of both immunoglobulin (Ig)-synthesizing and Ig-secreting B cells have been analyzed in DA-to-WF rat renal allografts (and in control WF-to-WF autografts). We have correlated the in situ B-cell responses with corresponding events in the central lymphatic system of the recipient. Intracellular IgM- and IgG-containing plasma cells appeared in an allograft (but not in an autograft) very shortly after the transplantation. The numbers of both cell types in situ was approximately equal, the highest numbers of each being found on Day 4 after transplantation. A similar early response was observed in the recipient's spleen, however, very few Ig-synthesizing cells were seen in the blood. Only a fraction of the Ig-synthesizing cells in the allograft were involved in immunoglobulin secretion. Thus, the recovery of IgG- and IgM-secreting cells from an allograft was 10 and 2% of intracellular IgG- and IgM-containing cells, respectively. It appears, therefore, that allograft-infiltrating Ig-synthesizing B cells either die or migrate elsewhere before secreting immunoglobulin. The B-cell response in the graft occurs very early and is disproportionally high when the very low frequency of B lymphocytes in the allograft is considered. The data provide no evidence for inflammatory B cells being an integral part of graft rejection. Indeed, the possibility remains that the inflammatory B-cell response observed during the rejection process represents a meaningless byproduct of the inflammatory response.     

In situ effector pathways of allograft destruction. 3. Plasminogen activator activity in rat renal allografts

The question of which cell components in a rejecting rat renal allograft secrete plasminogen activator (PA) has been analyzed. Although normal renal parenchymal cells also secreted PA, most of the PA in a renal allograft (and to a lesser extent also in an autograft) was produced by the inflammatory leukocytes. Fractionation at 1 g demonstrated that the inflammatory cell population responsible for the PA production in the allograft sedimented together with the large mononuclear phagocytes (macrophages). Fractions purified for small blast cells and large lymphocytes did not contain any PA activity but they were able to induce resting peritoneal macrophages to produce PA when cocultured in vitro. The results demonstrate that the allograft-infiltrating mononuclear phagocytes are "activated" in the sense that they secrete PA and that the activation of mononuclear phagocytes at the site of inflammation may be partially regulated by the inflammatory lymphoid cells.     

Sexual dimorphism in body composition changes during the pubertal period : As shown by French-Canadian children

Size and velocity growth curves of stature to represent skeletal growth, lean arm circumference to represent muscle growth, and the sum of three skinfolds to represent fat tissue changes, are presented for a longitudinal study of Montreal school–age children. Both a chronological age scale, and one relative to the individual ages of peak growth velocity in stature, are used. Intercorrelations between the various components are tabulated for age groups based on the two scales. The three skinfolds are also analyzed separately. The results show that such simple anthropometric measures can be usefully taken to represent the growth of different body components. Longitudinal analysis reveals that, whereas the relationship of muscular to statural growth in boys is purely maturational, it is not so for girls, and that the different skinfolds show complex sexual differences in growth during the pubertal period.     

Immunogenicity of allograft components: II. Relative immunogenicity of rat kidney parenchymal versus “passenger” cells

Well-perfused adult DA kidneys were enzymatically dispersed under conditions which do not affect the expression of cell surface major histocompatibility antigens. The kidney cell suspensions were separated via sedimentation at unit gravity into three fractions: I, rapidly sedimenting (>6.5 mm/hr) enriched for kidney tubular and glomerular cells and depleted of passenger leukocytes (76 and 8%, respectively); II, intermediate (5.1–6.0 mm/hr) mixed population equivalent to the unseparated kidney cell suspension (52% tubular and glomerular cells, 20% endothelial cells, and 28% passenger leukocytes); and III, slow sedimenting (<5.0 mm/hr) enriched for passenger leukocytes (63%). The three isolated fractions were analyzed for their ability to accelerate allograft rejection in the “primed heart rejection assay.” The cells in fraction I were unable to reduce heart allograft survival, while the cells from fraction III reduced it significantly. Cells from fraction II were intermediary effective. The results are in agreement with the hypothesis that the urine-producing apparatus of rat kidney is relatively nonimmunogenic, while the main stimulus for graft rejection is provided by the “passenger” cell component.     

Automatic cellulase assay in computer coupled pilot fermentation

Equipment for the automatic measurement of cellulase activity was connected to a computer-coupled pilot fermenter. The measurement was based on the use of dyed Avicel cellulose as substrate. An intermittent sampling device was used to take a sample from the fermenter at intervals of one hour. The computer was programmed to calculate the cellulase activity during fermentation. The measured activity values were corrected against a standard sample of known activity by means of a mathematical model for the calibration curve which was stored in the computer. On-line measurement of enzyme activity was successfully performed.     

Plasma catecholamine and serum testosterone responses to four units of resistance exercise in young and adult male athletes

The plasma noradrenaline (NA) and adrenaline (A) concentration responses of seven young male athletes [15 (SD 1) years] and seven adult male athletes [25 (SD 6) years] were investigated together with the serum testosterone (Tes) concentration responses in four different half-squatting exercises. The loads, number of repetitions, exercise intensity and recovery between the sets were manipulated such that different types of metabolic demand could be expected. However, the amount of work done was kept equal in each kind of exercise. After the most exhausting unit of exercise (E3; two sets of 30 repetitions with 50% of 1 repetition maximum and with 2-min recovery between the sets) the plasma NA concentration was significantly lower in the younger than in the adult subjects [15.7 (SD 7.8) vs 32.7 (SD 13.2) nmol · l⁻¹, P < 0.05], while the A concentrations were similar. In the other three exercises no differences in the plasma catecholamine concentration responses among the groups were observed. The postexercise Tes concentrations, however, were significantly lower in the younger than in the adult subjects in every exercise unit. No correlations between the plasma catecholamine and serum Tes concentration responses were observed in any of the exercise units in either group. The results of the present study may suggest reduced sympathetic nervous activity in the younger subjects compared to the adults in response to exhausting resistance exercise. The results may also suggest that the catecholamines were less involved in eliciting an increase in Tes secretion in these resistance exercises. Accepted: 11 November 1997     

Syntheses and structural study of bile acid amidoalcohols

Preparation, structural and thermoanalytical characterization of fourteen N-hydroxyalkyl 5beta-cholan-24-amides have been performed in this study. The utilized techniques include liquid state and CP-MAS (13)C NMR spectroscopy, thermogravimetry, differential scanning calorimetry, and also powder and single crystal X-ray crystallography. The results were discussed and compared to each other and also to previous findings on similar compounds. One pure hydrate form was obtained. Six new single crystal structures were determined, including one hydrated chloroform solvate. Decomposition temperatures were found to correlate with the side chain length, and the number of the hydroxyl groups. The spatial direction of the groups in the steroid skeleton was also found to be relevant in predicting the thermal properties of bile acid amidoalcohols studied.     

Post-stocking perturbations in a population of subarctic whitefish,Coregonus lavaretus (L.): effects on growth,condition and cestode infection

Lake Kilpisjärvi was stocked with a total number of 440 000 migratory and benthic whitefish fry during the period of 1959–1964. Thereafter, the Diphyllobothrium ditremum plerocercoid infection became a problem decreasing the feasibility and commercial exploitation of the whitefish stock. Since dense fish populations may cause stunting, all stockings in the study area were stopped in an attempt to enhance the fisheries. The aim of the present study was to explore the effect of the cessation of the stocking on the growth, condition, catches and D. ditremum infection of the whitefish population. A total of 1594 whitefish were sampled with benthic gill nets. Growth was estimated from length-at-age and mass–length relationship was estimated with a non-linear regression in 1982–1983, 1992–1993 and 1997. Parasite infection was studied in 1992–1993 and 1997. Growth and condition were poor in the beginning of the 1980s. In 1992–1993, the growth and condition of the fish improved as the numerical catch per unit effort decreased from 1982 to 1992. The mean catches of other fish species were low. There were no significant changes in whitefish growth or condition from 1992–1993 to 1997. From the 1970s to 1982–1983, during slow growth and poor condition of the fish, the median gillraker count was decreasing to 19 (min–max 14–26). In 1992–1993, the gillraker count had increased significantly to 23 (min–max 19–26). However, the improved growth and condition did not cause decrease in the D. ditremum burden. On the contrary, based on our own results and literature notes, the parasite abundance seems to increase during the observation period of 1964–1997.     

The effect of geometry and abduction angle on the stresses in cemented UHMWPE acetabular cups – finite element simulations and experimental tests

Background  

Contact pressure of UHMWPE acetabular cup has been shown to correlate with wear in total hip replacement (THR). The aim of the present study was to test the hypotheses that the cup geometry, abduction angle, thickness and clearance can modify the stresses in cemented polyethylene cups.