Crystallization and preliminary X-Ray diffraction characterization of a dimerizing fragment of the rod domain of the Dictyostelium gelation factor (ABP-120)

We have expressed in Escherichia coli a construct corresponding to sequence repeats 5 and 6 of the rod domain of the actin-binding protein Dictyostelium gelation factor (ABP-120). We have obtained orthorhombic P212121 crystals of the protein with a = 43.5 A, b = 103.2 A, c = 124.4 A. These crystals diffract past 2.2 A resolution using synchrotron radiation and are suitable for high-resolution structural analysis. ABP-120 is a key component of the Dictyostelium cytoskeleton, where it functions to crosslink F-actin filaments into networks. This crosslinking function of ABP-120 depends crucially on the formation of dimeric molecules that contain an actin-binding site on each chain, and this dimerization is brought about through interactions between repeating sequence modules in the rod domain. Because the construct we have expressed retains the ability to dimerize, it should enable us to establish the precise manner in which these sequence repeats interact with one another in the intact molecule.     

Frequency and significance of anti-gliadin and anti-endomysial antibodies in autoimmune hepatitis

Celiac disease has been associated with autoimmune disorders, but its frequency in autoimmune hepatitis is unknown. Sera from 157 patients with type 1 autoimmune hepatitis, 24 patients with type 2 autoimmune hepatitis, 62 patients with primary biliary cirrhosis, 30 patients with chronic hepatitis B, and 80 patients with chronic hepatitis C were tested for immunoglobulin A anti-endomysial antibodies by indirect immunofluorescence and immunoglobulin A and G antibodies to gliadin by enzyme immunoassay. Duodenal biopsy evaluation was recommended in patients seropositive for immunoglobulin A anti-endomysial antibodies. Immunoglobulin A anti-endomysial antibodies were present in eight of the 181 patients with autoimmune hepatitis (4%), including six with type 1 disease (4%) and two with type 2 disease (8%). Immunoglobulin A antibodies to gliadin were found in six of these eight patients, but they were also present in two others, including one patient with chronic hepatitis C. Five of the eight patients with immunoglobulin A antiendomysial antibodies, including three patients with no gastrointestinal symptoms, had duodenal biopsies and subtotal villous atrophy was present in all of them. No patient with primary biliary cirrhosis or chronic viral hepatitis had antiendomysial antibodies. The presence of celiac disease in autoimmune hepatitis is high (at least one in 36 patients) and it is predominantly asymptomatic. Screening with anti-endomysial and anti-gliadin antibodies should be performed and results confirmed with intestinal biopsy.     

Dialysis arthropathy: identification and evaluation of a subset of patients with unexplained inflammatory effusions

OBJECTIVE: Rheumatic disorders have been reported in patients with chronic renal failure treated with hemodialysis. We identified and evaluated 9 patients undergoing hemodialysis with inflammatory joint effusions not explained by known causes such as gout and bacterial infection. METHODS: Forty-nine consecutive synovial fluid (SF) analyses on 41 dialysis patients were reviewed. Nine with unexplained inflammatory arthritis were studied in detail. SF analysis included polarized light examination, alizarin red S stain, Congo red stain, cultures, transmission electron microscopy, and electron probe elemental analysis. RESULTS: SF leukocyte counts ranged from 4550 to 36,000/mm3 with 44-98% neutrophils. No infections were identifiable in these patients. Findings evaluated as possible factors in the joint inflammation included apatite crystals, iron, lipids, amyloid, and difficult to diagnose nonbacterial infections such as hepatitis C. CONCLUSION: Some highly inflammatory joint effusions in patients undergoing chronic hemodialysis are not due to pyogenic infections and may be attributable to other factors.     

Reversion to back-up mode (VOO) in a DDD pacemaker model

Sorin recently identified mode reversion to backup mode (VOO). They estimate a prevalence of 1% and suggest electromagnetic interference (EMI) as the cause. We identified ten patients being followed in our pacing clinic, of whom four were found to have suffered mode reversion. We, therefore, conclude that the prevalence of this problem may be greater than predicted. None of the patients who were found to have mode reversion gave any history to suggest that they had been exposed to EMI.     

Low-frequency periodicity in the coordination of progressive handwriting

The paper addresses the question how the effector segments are coordinated during handwriting, in particular as a function of the left-to-right progression within words. It studies the phase relations between wrist and finger-joint rotations during a repetitive graphic task (long words consisting of letters 'e'), and it subjects the resulting continuous phase-relation plots to autocorrelation analysis. A novel phenomenon, viz. that of low-frequency (1-Hz) periodicity, is observed which presumably reflects adjustments of the coordination pattern about once per second, i.e., after every three or four letters 'e'. Moreover, word length and word position are found to affect this periodicity in a predictable manner. These results are related to those of an earlier study which used an ad-hoc method of analysing wrist-finger coordination adjustments. The paper underlines the value of phase-relation analysis for certain graphic tasks, but it also points out its limitations for this purpose.     

Genetic distribution of Bare-1-like retrotransposable elements in the barley genome revealed by sequence-specific amplification polymorphisms (S-SAP)

Acid anhydrides are highly reactive, low molecular weight compounds that are used widely in industry. Work-related exposure to this group of substances may cause occupational asthma. Because of low molecular weight, these compounds are not able to induce antibody responses without conjugating with human proteins. Acid anhydrides may act as haptens when conjugated with human serum albumin (HSA). The induction mechanism of immediate and late bronchial hyperresponsiveness to acid anhydrides appears to be at least partly mediated by IgE antibodies. Other clinical syndromes, which may be caused by acid anhydrides such as pulmonary disease-anemia (PDA), and late respiratory systemic syndrome (LRSS) associated with TMA exposure, appear to be associated with IgG antibodies to TMA as well as with IgE. Significant cross-reaction occurs between different compounds of this group, particularly regarding IgE antibodies. As inhalational exposure to acid anhydrides may result in serious pulmonary disease, adequate protection of potentially exposed workers or their removal, if affected, from exposure is essential.     

p53 is phosphorylated in vitro and in vivo by the delta and epsilon isoforms of casein kinase 1 and enhances the level of casein kinase 1 delta in response to topoisomerase-directed drugs

The p53 tumour suppressor protein plays a key role in the integration of stress signals. Multi-site phosphorylation of p53 may play an integral part in the transmission of these signals and is catalysed by many different protein kinases including an unidentified p53-N-terminus-targeted protein kinase (p53NK) which phosphorylates a group of sites at the N-terminus of the protein. In this paper, we present evidence that the delta and epsilon isoforms of casein kinase 1 (CK1delta and CK1epsilon) show identical features to p53NK and can phosphorylate p53 both in vitro and in vivo. Recombinant, purified glutathione S-transferase (GST)-CK1delta and GST-CK1epsilon fusion proteins each phosphorylate p53 in vitro at serines 4, 6 and 9, the sites recognised by p53NK. Furthermore, p53NK (i) co-purifies with CK1delta/epsilon, (ii) shares identical kinetic properties to CK1delta/epsilon, and (iii) is inhibited by a CK1delta/epsilon-specific inhibitor (IC261). In addition, CK1delta is also present in purified preparations of p53NK as judged by immunoanalysis using a CK1delta-specific monoclonal antibody. Treatment of murine SV3T3 cells with IC261 specifically blocked phosphorylation in vivo of the CK1delta/epsilon phosphorylation sites in p53, indicating that p53 interacts physiologically with CK1delta and/or CK1epsilon. Similarly, over-expression of a green fluorescent protein (GFP)-CK1delta fusion protein led to hyper-phosphorylation of p53 at its N-terminus. Treatment of MethAp53ts cells with the topoisomerase-directed drugs etoposide or camptothecin led to increases in both CK1delta-mRNA and -protein levels in a manner dependent on the integrity of p53. These data suggest that p53 is phosphorylated by CK1delta and CK1epsilon and additionally that there may be a regulatory feedback loop involving p53 and CK1delta.