ATRX encodes a novel member of the SNF2 family of proteins: mutations point to a common mechanism underlying the ATR-X syndrome

It was shown recently that mutations of the ATRX gene give rise to a severe, X-linked form of syndromal mental retardation associated with alpha thalassaemia (ATR-X syndrome). In this study, we have characterised the full-length cDNA and predicted structure of the ATRX protein. Comparative analysis shows that it is an entirely new member of the SNF2 subgroup of a superfamily of proteins with similar ATPase and helicase domains. ATRX probably acts as a regulator of gene expression. Definition of its genomic structure enabled us to identify four novel splicing defects by screening 52 affected individuals. Correlation between these and previously identified mutations with variations in the ATR-X phenotype provides insights into the pathophysiology of this disease and the normal role of the ATRX protein in vivo.      

Retinoic acid inhibits CD40 plus IL-4 mediated IgE production through alterations of sCD23, sCD54 and IL-6 production

Background: All-trans retinoic acid (ATRA) inhibits IgE synthesis from anti-CD40 plus IL-4 stimulated human B lymphocytes.Objective: To study the underlying mechanisms, we examined here molecules which are known to have an impact on IgE production, namely CD23, CD54 and IL-6.Methods: Human anti-CD40 plus IL-4 stimulated B cells were cultured in the absence and presence of ATRA (10^–6–10^–10 M). ELISAs were performed to determine soluble (s) CD23 and sCD54, IL-6 and IgE-levels. CD23 and CD54 surface expression were determined by flow cytometric analysis. Semiquantitative-RT-PCR was employed to analyse IL-6, CD23 and CD54 mRNA expression.Results: ATRA induced a dose-dependent increase of percent CD23 (3.4 fold) or CD54 (1.6 fold) positive B cells. At the mRNA level, this was reflected by a modest increase of CD54 mRNA (46.5 ± 15.8%) only. By contrast, levels of sCD54 were decreased dose-dependently in the presence of ATRA (56.6 ± 7.6%). Cytokine analysis showed that IL-6 secretion was significantly inhibited by ATRA (53.6 ± 0.6%) and also IL-6 mRNA synthesis was reduced (66.3 ± 11.6%). The observed inhibition of IgE production mediated by ATRA was significantly reversed to 90.5 ± 12% by the addition of 100 pg/mL recombinant IL-6.Conclusions: ATRA interferes through several pathways with the anti-CD40 plus IL-4 mediated B cell activation, namely IL-6, CD23 and CD54.Received 8 June 2004; returned for revision 19 July 2004; accepted by M. J. Parnham 5 November 2004     

C1q binding substances in pemphigus and bullous pemphigoid. Detection with a [131I] C1q binding assay.

A modification of the [125I]C1q binding assay was developed to allow the estimation of C1q binding activity (C1q BA) in pemphigus and bullous pemphigoid sera. The modifications include lower final concentration of PEG 6000 (1-5%) which permitted the use of sera that had been stored at -20 degrees C for extended periods of time; use of 131I instead of 125I and an [131I] C1q concentration of 5 microng/ml rather than 1 microng/ml. EDTA was used at a final concentration of 0-13 M to obviate the need for heat inactivation of sera. Sera from seventy-one patients with pemphigus and from 142 patients with bullous pemphigoid were tested for C1q BA. Of these 40% of the pemphigus and 20% of the bullous pemphigoid patients showed elevated C1q BA. A relationship between elevated C1q BA in serum and active disease was noted. Sequential samples from forty patients with pemphigus and thirty-seven patients with bullous pemphigoid demonstrated two different types of relationship between serum antibody titres to cutaneous antigens and C1a BA. In some patients serum antibody titres and C1q BA increased and decreased simultaneously; in others, increase of C1q BA followed increase of antibody titre and coincided with its decrease. The latter relationship supports the hypothesis that C1q BA may represent at least in part antigen-antibody complexes containing cutaneous antigens.     

Assessment of bioequivalence after subcutaneous and intramuscular administration of urinary gonadotrophins

The objective was to demonstrate bioequivalence between s.c. and i.m. administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio 3:1). In two randomized, single-centre, cross-over studies, 18 healthy volunteers on each formulation were assigned to one of the two administration sequences. Subjects were given single doses of one of the above gonadotrophins after endogenous gonadotrophin production had first been suppressed using high-dose oral contraceptive. Subsequently, rate (Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax and AUC, analysis of variance (ANOVA) was performed on log-transformed data and for tmax ANOVA was performed on ranks. Intramuscular and s.c. injections of Humegon were bioequivalent with respect to the main pharmacokinetic parameters, being AUC and Cmax of FSH absorption. Intramuscular and s.c. injections of Normegon were bioequivalent with respect to the AUC of FSH and not bioequivalent with respect to the Cmax of FSH. For tmax of FSH as well as for most LH variables of both preparations, bioequivalence could not be proven due to the high intra- and interindividual variability and/or concentrations being close to the detection limit. Thus, the main pharmacokinetic FSH variables after i.m. and s.c. administration of Humegon and Normegon were bioequivalent.      

Infectious bursal disease virus structural protein VP 2 expressed by a fowlpox virus recombinant confers protection against disease in chickens

Summary Two fowlpox virus recombinants were constructed which expressed the host-protective antigen, VP 2, of infectious bursal disease virus (IBDV). Recombinant FPV-VP 2.4.3 contained the gene for the VP 2-VP 4-VP 3 polyprotein under the control of the vaccinia virus late promoter P.L 11 inserted within the thymidine kinase (TK) gene of FPV. In infected chicken embryo skin (CES) cells VP 2 and VP 3 proteins were correctly processed from the polyprotein precursor molecule. Recombinant FPV-VP 2 contained only the VP 2 encoding region under the control of the fowlpox early/late promoter P.E/L inserted immediately downstream of theTK gene. The expression level of VP 2 from FPV-VP 2 was approximately 5 times higher than from FPV-VP 2.4.3. Wing web inoculation of birds resulted in the development of typical fowlpox lesions and the development of antibodies to FPV with either of the recombinants, but only birds vaccinated with FPV-VP 2 developed antibodies to IBDV. When challenged with IBDV (strain 002-73), a significant level of protection was provided by FPV-VP 2 vaccination, although the level was lower than the protection provided by an oil adjuvanted inactivated whole IBDV vaccine. Birds vaccinated with FPV-VP 2.4.3 were not protected from infection as assessed by ELISA for the presence of IBD virus in bursae.     

Enhanced proliferation of endogenous virus in Chinese hamster cells associated with microtubules and the mitotic apparatus of the host cell.

Chinese hamster ovary cells harbour intracytoplasmic virus-like particles of type A which are closely associated with sites of microtubule formation. We report here the enhanced proliferation of these particles and their release at the cell membrane by using either 5-bromodeoxyuridine or dibutyryl cyclic AMP. The extracellular mature particles are similar in morphology to retroviruses of type B. Close association of the type A virus precursors with microtubule organizing centres, i.e. kinetochores, centrioles and basal bodies, and with microtubules per se, is confirmed by studying the effects of the microtubule inhibitors Colcemid and vincristine sulphate. The role of microtubules in the activation and transport of the intracytoplasmic type A particles is discussed.     

Biological resurfacing of the knee: a review of surgical management

Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee.