Pseudodicentric chromosome 18 diagnosed by chromosome painting and primed in situ labelling (PRINS).

We report on a newborn white male infant with marked dysmorphic features and various congenital malformations. The initial clinical evaluation showed Crouzon-like features as well as some features of trisomy 18 syndrome and trisomy 13 syndrome. The results from conventional cytogenetic analysis showed a structurally abnormal chromosome replacing one normal chromosome 18, but only by applying molecular cytogenetic methods could the architecture of this abnormal chromosome be characterised clearly. The primed in situ labelling (PRINS) technique, using a newly synthesised alpha 18 oligonucleotide, showed the dicentric pattern and direct chromosome painting established the origin to be from chromosome 18. The combination of conventional cytogenetics and molecular cytogenetics showed the karyotype in the proband to be 45,XY,-14,-18,-21,+t(14;21),+psu dic(18) (qter-->cen-->p11.3: :p11.3-->psu cen-->qter). This was supported by molecular analysis using chromosome 18 specific DNA markers, which showed the paternal origin of the abnormal chromosome.     

Thrombocytopenia in a retrovirally-induced murine erythroleukemia.

A variant strain of Rauscher leukemia virus (RLV-A) obtained from a transplantable murine monomyelocytic leukemia causes a disease characterized by frank anemia, wasting, hepatosplenomegaly and erythroblastosis. The involvement of platelets in this disease are reported here. The RLV-A induced a severe thrombocytopenia (25 percent of control level) at the terminal stage of disease. This thrombocytopenia was not associated with disseminated intravascular coagulopathy since the prothrombin times were always within normal limits. The partial thromboplastin time was elevated in the terminal stages of disease and was found to be associated with factor deficiencies, possibly owing to the presence of anti-factor antibodies, in the intrinsic coagulation pathway, especially factor VIII. Further, splenectomy did not abolish the thrombocytopenia, since splenectomized, virally infected animals also developed severe thrombocytopenia (29 percent of control levels). The ensuing splenomegaly during progression of disease was not the cause of the thrombocytopenia. A physiological response to the severe thrombocytopenia was the production of larger size platelets. At terminal stages of the disease, platelet volume increased to 4.2 mu 3 (normal is 3.0 mu 3). An increase in platelet volume was also observed in splenectomized, virally infected animals. Electron microscopy indicated that these circulating platelets contained c-type viral particles. Viral infection was associated with decreased life span of circulating platelets, as measured by 75Se-methionine at mid and terminal stages of the disease. Our results suggest that direct viral infection of platelets and/or megakaryocytes with subsequent cell lysis is a possible cause of the observed thrombocytopenia observed in RLVA-induced disease and may also occur in other retrovirally-induced diseases.     

Serum antibodies to Pseudomonas aeruginosa outer-membrane proteins and iron-regulated membrane proteins at different stages of chronic cystic fibrosis lung infection

Serum samples collected over periods up to 15 years from nine patients with cystic fibrosis (CF) were investigated by immunoblotting and crossed immuno-electrophoresis (CIE) for antibodies to Pseudomonas aeruginosa outer-membrane proteins (OMPs). The earliest antibody response to OMPs was directed against proteins G, H1 and I. Detection by immunoblotting sometimes preceded the CIE response; the appearance of antibodies to the other major OMPs was co-incident with an increase in CIE precipitins. Isolation of the mucoid form of P. aeruginosa was associated with a rapid increase in both precipitin numbers and antibodies detected by immunoblotting. Antibodies to iron-regulated OMPs could be detected in all the serum samples that showed eight or more CIE precipitins but their presence became pronounced only in the advanced stages of disease. The clinical strain used in this study and other isolates from CF patients showed several atypical OMPs, perhaps as a consequence of antibiotic therapy or related to the serum sensitivity of mucoid P. aeruginosa. Their expression in vivo was confirmed by detecting antibodies to them in patients' serum.     

Anti-diabetogenic effect of fusidic acid in diabetes prone BB rats.

Fusidic acid and its sodium salt (fusidin) are anti-staphylococcal drugs. In vitro studies have shown that they prevent the lymphocyte co-stimulatory activities of the cytokines IL-1 and IL-6 in a manner similar to that of cyclosporin A, and prevent the inhibitory effect of IL-1 on glucose-induced insulin production. As IL-1 and IL-6 are thought to play a role in the pathogenesis of Type 1 diabetes, the aim of this study was to investigate whether fusidin could influence the disease incidence of the spontaneously diabetic BB rat model. Accordingly, a group of 50 BB rats receiving fusidin dissolved in their drinking water were compared to a control group of 55 rats over a period of 200 days. The incidence of diabetes was found to be 52% in the experimental group and 71% in the control group (P < 0.05). The degree of insulitis and the number of islets at histological examination were similar among the non-diabetic animals whereas the diabetic fusidin-treated animals showed a higher degree of islet preservation than the diabetic control rats. The results are highly indicative of an anti-diabetogenic effect of fusidin.     

Methodologic problems in establishing normal values for IgG subclass concentrations in a pediatric population; comparison of radial immunodiffusion and ELISA methods

The aim of this study was to establish an enzyme-linked immunosorbent assay (ELISA) to measure IgG subclasses by means of monoclonal antibodies. The distribution of IgG subclass protein concentrations in sera from 227 healthy Danish children and 90 adults was measured. Furthermore, this newly established ELISA was compared with different assay systems for determination of IgG subclasses: two radial immunodiffusion methods (RID), one using polyclonal and one using monoclonal antibodies, as well as a commercially available ELISA kit. There was good agreement of results obtained by the different methods of measuring IgG3 and IgG4 concentrations. There was good correlation between results obtained by both RID methods. Despite good correlation between the assays, the ELISA kit showed higher levels of IgG1 in all investigated sera, and the ELISA kit showed no correlation with the other methods, when IgG2 was measured. Analysis of the normal ranges measured by ELISA developed in our laboratory and by RID with polyclonal antibodies showed that the levels obtained by RID were higher than those obtained by our ELISA in sera with low levels of both IgG1 and IgG2, and lower in sera with high concentrations of these two immunoglobulins. Our results emphasize the importance of establishing age-related normal limits for any novel assay measuring IgG subclass concentrations.     

Cytokine-induced histamine release from basophils of AIDS patients

Basophil leukocytes obtained from AIDS patients, allergic patients and healthy controls were stimulated in vitro with interleukin 4, lymphotoxin, tumour necrosis factor alpha and interferon gamma to examine the histamine releasing effect. The cytokines caused histamine release from the basophils of approximately half the AIDS patients and from 8-17% of the allergic patients. No response was obtained in the control group. Removal of cell surface immunoglobulins abolished the response to cytokines, indicating an Ig-dependent mechanism. Passive sensitization with cell-derived Ig, with Ig deprived of IgE, or with IgG, indicated that cell-bound IgE was responsible for the cytokine-induced histamine release in AIDS patients. This response may be mediated by cytokine-selective IgE antibodies.     

Immunological Studies on the Envelope Component of Venezuelan Equine Encephalomyelitis Virus

Treatment of purified Venezuelan equine encephalomyelitis virus with the nonionic detergent Triton X-100 permitted spearation of the envelope from the core component. The isolated envelope was a noninfectious immunogen which reacted in hemagglutination, hemagglutination inhibition, complement fixation, and neutralization serological reactions.