Milica Trbojević-Čepe

Comparison of the values of basic fibroblast growth factor determined by an immunoassay in the sera of patients with traumatic brain injury and enhanced osteogenesis and the effects of the same sera on the fibroblast growth in vitro.

In patients with severe traumatic brain injury, the early healing of fractures is accompanied by hypertrophic callus formation or heterotopic ossifications, which might even result in ankylosis of the affected joints. Analysis of the sera of patients with traumatic brain injury revealed post-traumatic dynamic changes of basic fibroblast growth factor immunoreactivity, similar to those observed during fracture healing associated with enhanced osteogenesis. The aim of this study was to determine whether such changes in basic fibroblast growth factor concentrations could be related to the phenomenon of enhanced osteogenesis. Basic fibroblast growth factor immunoreactivity was determined (using an IEMA kit) in the sera of patients with traumatic brain injury and bone fractures (n = 8) and in the sera of patients with either traumatic brain injury alone (n = 10) or bone fractures alone (n = 7), and the effects of these sera on L929 fibroblast growth were analysed in vitro. The results did not prove a causative relationship between the changes of basic fibroblast growth factor immunoreactivity and in vitro growth promoting effects of the sera. However, it is apparent that, in addition to changes in the growth-promoting activity and basic fibroblast growth factor concentration of serum, other as yet unknown post-traumatic changes can cause enhanced osteogenesis.

Cerebrospinal fluid complement activation in neurological diseases

Laser nephelometry (LN) is a rapid and very sensitive method for simultaneous determination of albumin, immunoglobulins, C3c and C4 in diluted serum and paired cerebrospinal fluid (CSF) samples. It is very useful in routine analyses. Determination of C3c and C4 covers classical as well as alternative pathways of complement activation. In CSF, they are mostly derived from and related to serum values. Under physiological conditions, the addition of intrathecal C4 synthesis is likely. The incidence of complement activation within CSF is also influenced by the method of choice (native molecules, activation products and complexes, inhibitors) and the mode of interpretation of results according to the functional state of the blood-brain barrier (BBB). Calculation of indexes and the modified Reibers graph method are valid means of detection of complement activation within CSF. Complement activation within CSF was confirmed in 36% (111/302) of neurological patients examined; in 55% (48/87) of patients with inflammatory and demyelinating diseases, in 40% (37/94) of patients with CNS infections and complications, in 33% (4/12) of patients with motor neuron diseases, in 27% (11/40) of patients with spinal cord compression and sequelae, in 25% (8/32) of patients with neoplastic disease, and in 17% (6/37) of patients with cerebrovascular accidents.

Interleukin 4, IgG and oligoclonal IgG in aqueous humor of cataract patients

We measured interleukin 4, total IgG, IgG-albumin relative concentration ratio, and oligoclonal IgG in aqueous humors of patients with uncomplicated senile cataracts and cataracts complicated by previous uveitis of unknown etiology. The values of all mentioned parameters are significantly elevated in aqueous humors of patients with complicated cataracts. The possible implications of our findings are briefly discussed.

Apolipoprotein H (apoH)-dependent autoantibodies and apoH protein polymorphism in selected patients showing lupus anticoagulant activity

Abstract Apolipoprotein H (apoH) is considered to be a necessary cofactor for the binding of certain antiphospholipid antibodies to anionic phospholipids. Some apoH-dependent antiphospholipid antibodies also exert lupus anticoagulant (LA) activity, which seems to depend on antiphospholipid antibody epitope specificity. The aim of this study was to evaluate whether the presence of less frequent apoH alleles may induce structural or conformational changes in these “LA-dependent” regions that may initiate more frequent autoimmune responses in subjects. We selected patients with confirmed LA activity and none or low titers of anticardiolipin antibodies that had been sent to the laboratory for routine antiphospholipid antibody determination. Many of them had some clinical manifestation of antiphospholipid syndrome. Antibodies to apoH were determined with a commercially available anticardiolipin/apoH ELISA kit. ApoH protein polymorphism (apoH phenotype) was demonstrated by isoelectric focusing and immunoblotting. Our results showed that 47/74 (63.5%) of our selected LA-positive patients also had elevated apoH-dependent antiphospholipid antibody titers. These results point to two subgroups of patients according to the LA potency of apoH-dependent antibodies. A strong positive correlation (non-linear or linear) for apoH-dependent antibody titers and LA activity was observed in both subgroups of patients. In this study, we did not find significant differences in the distribution of apoH phenotypes among control subjects and patients with apoH-dependent/LA-positive auto- antibodies.