Mumps antibodies of 34 human beings were studied, 12 patients with natural mumps infection, 15 subjects vaccinated with a live mumps vaccine, and seven subjects vaccinated with an inactivated vaccine. Small amounts of antibodies reacting with mumps antigen were found in the prevaccination sera. An immunization with either the live or the killed vaccine caused an increase in the mumps antibodies (range, from 1.1‐fold to more than 50‐fold; geometric mean, approximately sevenfold). IgG1 was the major isotype in all post‐vaccination sera; the averag share was 61%. Next came IgM (28%), followed by IgA (9%), and IgG3 (2% of total). The patient samples had 10 (acute phase) or 20 times (convalescent phase) more mumps antibodies than the prevaccination samples. IgGl was the predominant isotype in the acute phase sera (average 42% of all antibodies). Next came IgM (41%) followed by IgA (13%), and IgG3 (4%). In convalescent sera IgGl was also the predominant isotype (average 67%), followed by IgM (19%). The minor isotypes in the second samples were IgA (12%) and IgG3 (3%). Small amounts of IgG2 antibodies were found in 1 patient and 1 vaccinee. IgG4 antibodies were not detected.
Impaired postnatal growth in very low birth weight (VLBW, <1500 g) infants is per se a major clinical challenge and may also serve as a model in studying the mechanisms of growth retardation in general. This study was undertaken to characterize the role of IGFs and their binding proteins (IGFBPs), key regulators of fetal and infant growth, during the postnatal period in VLBW infants. Forty-eight VLBW infants (gestational age 27.6 +/- 2.2 wk, birth weight 923 +/- 257 g) were studied. Blood samples were drawn at 1, 2, 4, and 8 wk of age for measurements of IGF-I, IGFBP-1 (lesser phosphorylated, lpIGFBP-1, and highly phosphorylated, hpIGFBP-1), IGFBP-3, and insulin, simultaneous growth velocities being assessed by a rigorous protocol of repeated, frequent lower leg length and body weight measurements. All regression analyses were adjusted for postnatal age and repeated measurements. Lower leg growth velocity showed a positive correlation with IGF-I (P = 0.01) and IGFBP-3 (P = 0.03), and weight growth velocity with IGFBP-3 (P = 0.057) and with lpIGFBP-1/hpIGFBP-1 ratio (P = 0.01). Moreover, concurrent glucocorticoid dose showed a negative correlation with both IGFBP-1 isoforms, observable, however, only in samples with high (>10 U/liter) insulin (lpIGFBP-1, P = 0.02; hpIGFBP-1, P = 0.007). In backward multiple regression analysis, the factor remaining significantly associated with lower leg growth velocity (R(2) = 0.63) was IGF-I, and factors associated with weight growth velocity (R(2) = 0.81) were IGFBP-3 and the lpIGFBP-1/hpIGFBP-1 ratio. In conclusion, circulating IGF-I and IGFBP-3, and the lpIGFBP-1/hpIGFBP-1 ratio, reflect short-term growth velocity in VLBW infants. lpIGFBP-1 isoforms, abundant in the circulation of these infants, may thus also have properties that are at least less inhibitory, if not promoting, on the growth-stimulating action of IGF-I. Finally, the regulation of IGFBP-1 by glucocorticoids may be divergent in situations with a high or low insulin concentration.
Proteins that decrease the surface activity of surfactant accumulate in epithelial lining fluid in respiratory failure. The aim of this study was to isolate a surfactant inhibitor from the airways of rabbits in acute respiratory failure induced by bronchoalveolar lavage (BAL). This inhibitor was identified as being transferrin (TF). Unlike serum TF, TF recovered in respiratory failure was saturated with iron (Fe(3+)-TF). Fe(3+)-TF decreased the surface activity of normal surfactant in vitro, whereas iron-free TF had no effect. In the presence of H2O2 and a reducing agent, Fe(+3)-TF inactivated the surfactant complex: the surface absorption rate was decreased, immunoreactive surfactant protein A was decreased, and malondialdehyde was formed. The acute effects of Fe(3+)-TF and iron-free TF applied to the airways were studied in animal models. In respiratory failure induced by BAL, Fe(3+)-TF deteriorated respiratory failure, whereas iron-free TF had no effect. In respiratory failure induced by hyperoxia for 48 h, administration of iron-free TF ameliorated the respiratory failure and improved the surface activity in BAL. We propose that Fe(3+)-TF accumulating in epithelial lining fluid during lung damage contributes to surfactant inhibition and promotes the formation of free radicals that inactivate the surfactant system.
120 Serum reticulin and endomysial autoantibodies are highly coeliac disease(CD)-specific. The autoantigens are preserved among both rodents and primates, including humans. A calcium-dependent enzyme tissue transglutaminase (tTG) has been shown to represent the predominant endomysial autoantigen in CD. We evaluated whether IgA-class tTG autoantibodies might be a useful tool in CD diagnosis. Sera of 134 patients with untreated CD and 207 disease controls were studied. tTG in phosphate-buffered saline or in calcium-containing Tris-buffered saline, pH 7.5, was used as antigen in an enzyme-linked immunosorbent assay (ELISA). Serum IgA-class endomysial antibodies (HUC-ab) were determined by an indirect immunofluorescence method using human umbilical cord as substrate and fluorescein-conjugated (FITC) antibodies as secondary antibody. IgA-class gliadin antibodies (AGA) were tested with an ELISA method. Calcium-treated and - untreated Western blots were performed with CD patient serum IgA, healthy control serum IgA and with mouse monoclonal tTG antibody CUB 7402 (MAb tTG). The antigen detected by MAb tTG was examined with the indirect immunofluorescence method using rhodamine-conjucated (TRITC) antiserum as secondary antibody. CD associated IgA did not specifically detect calcium-untreated tTG in ELISA. However, calcium-treated tTG autoantibody ELISA test proved to be highly sensitive, as 127 of 134 (95%) untreated CD patients were positive. The best cut-off limit was calculated to be 10 arbitrary units. Thirteen out of 207 disease control patients had slightly elevated titres (specificity 94%). Ten out of thirteen IgA-deficient CD patients were detected by IgG-class tTG autoantibody ELISA. The sensitivity for the IgA-class HUC-ab test was 92% and the specificity 100%. The results for AGA were 84% and 89%, respectively. tTG autoantibody ELISA test correlated better to the HUC-ab test than to the AGA test. MAb tTG detected proteins of higher molecular weight in immunoblot with calcium-treated tTG than in blot with untreated tTG. Double immunofluorescence staining (FITC/TRITC) with CD patient serum and with MAb tTG showed a complete overlapping in human umbilical cord, including both vessel smooth muscle endomysium and Wharton's jelly fibroblasts. In conclusion, tTG autoantibodies are highly sensitive and specific indicators for untreated CD. Calcium is needed for specific antibody detection. ELISA for the identified autoantigen allows an economical and rapid large-scale screening for CD. It also eliminates the observer bias always possible in immunofluorescent techniques.
Oxygen free radical generation by xanthine oxidase (XO) is a possible mechanism in the injury following reperfusion of transplanted organs. This study was undertaken to investigate XO in human lung, and to investigate whether XO is released into the blood stream during the immediate postoperative period after lung transplantation. XO activity was measured in healthy human lung tissue, and XO protein and the adenine nucleotide catabolic products hypoxanthine, xanthine and uric acid were analysed in the plasma samples collected during human heart-lung transplantation (n=4), double lung transplantation (n=2), and single lung transplantation (n=1). Neutrophil degranulation was assessed by plasma lactoferrin measurements. The results indicated that XO activity (detection limit 5 pmol x min(-1) x mg(-1) protein) and protein (detection limit 5 ng x mg-1 protein) were undetectable in the lungs of five healthy individuals. Similarly, no XO protein could be found in the plasma samples from the right ventricle or left atrium during and after the transplantation in any of the cases. Plasma xanthine and hypoxanthine concentrations were elevated 2-10 fold immediately after the reperfusion of the transplant, indicating washout of high-energy phosphate degradation products from the ischaemic lung. Plasma uric acid decreased rather than increased immediately after the surgery and during the following 24 h. Lactoferrin was elevated during the surgery. In conclusion, these results show that XO activity in human lung is low, it is not released into the blood stream during human heart-lung transplantation, and it is unlikely to contribute to postoperative complications in these patients.
