Expression of recombinant antigens in Escherichia coli: application on immunochemical studies of Schistosoma mansoni tegumental antigens

Sm15 and Sm13 are recognized by antibodies from mice protectively vaccinated with tegumental membranes, suggesting a potential role in protective immunity. In order to raise antibodies for immunochemical investigations, the genes for these antigens were expressed in pGEX and pMal vectors so that comparisons could be made among different expression systems and different genes. The fusion proteins corresponding to several parts of the gene for the precursor of Sm15 failed in producing antibodies recognizing the parasite counterpart. On the other hand, antibodies raised against Sm13 MBP-fusion proteins recognized the 13 kDa tegumental protein. Thus the peculiarities of the gene of interest are important and the choice of the expression system must sometimes be decided on an empirical basis.     

Edible vaccine protects mice against Escherichia coli heat-labile enterotoxin (LT): potatoes expressing a synthetic LT-B gene

The authors have designed and constructed a plant-optimize synthetic gene encoding the Escherichia coli heat-labile enterotoxin B subunit (LT-B), for use in transgenic plants as an edible vaccine against enterotoxigenic E. coli. Expression of the synthetic LT-B gene in potato plants under the control of a constitutive promoter yielded increased accumulation of LT-B in leaves and tubers, as compared to the bacterial LT-B gene. The plant-derived LT-B assembled into native pentameric structures as evidenced by its ability to bind ganglioside. The authors demonstrated immunogenicity by feeding mice the raw tubers and comparing the anti-LT-B serum IgG and faecal IgA to that produced in mice gavaged with bacterial LT-B. Mice were fed three weekly doses of 5 g tuber tissue containing either 20 or 50 micrograms LT-B, or gavaged weekly with 5 micrograms of LT-B from recombinant E. coli. One week after the third dose, mice immunized with potato LT-B had higher levels of serum and mucosal anti-LT-B than those gavaged with bacterial LT-B. Mice were challenged by oral administration of 25 micrograms LT, and protection assessed by comparing the gut/carcass mass ratios. Although none of the mice were completely protected, the higher dose potato vaccine compared favourably with the bacterial vaccine. These findings show that an edible vaccine against E. coli LT-B is feasible.     

Anesthetic considerations in the child with Gaucher disease

Alpidem, an imidazopyridine that acts at the gamma-aminobutyric acid/benzodiazepine receptor complex, has been reported to be an effective anxiolytic with a more favorable side effect profile than benzodiazepines. The effect of alpidem was investigated in an 8-week, open, clinical trial in 13 patients with panic disorder, with or without agoraphobia. Three patients were responders (much improved or very much improved), five patients were nonresponders, and five patients dropped out after less than 6 weeks of treatment. Significant improvement was seen in the sample as a whole for spontaneous panic attacks, phobic avoidance, and anticipatory anxiety. Most improvement occurred during the first 4 weeks of treatment, and responders had milder panic disorder at baseline. Adverse effects were generally mild. After 8 weeks of treatment, taper of medication over 2 weeks occurred without significant worsening of panic disorder symptoms. The efficacy of alpidem in the treatment of panic disorder remains uncertain and requires assessment in a controlled trial.     

A cdc2-like kinase associated with commitment to division in Paramecium tetraurelia

Cell division in higher eukaryotes is mainly controlled by p34cdc2 or related kinases and by other components of these kinase complexes. We present evidence that cdc2-like kinases also occur in Paramecium. Two polypeptides reacted with an antibody directed against the perfectly conserved PSTAIR region found in cdc2 kinases in other eukaryotes. Only the less abundant peptide bound to p13suc1 from Schizosaccharomyces pombe. Using centrifugal elutriation to select cells on the basis of size, we isolated highly synchronous Paramecium G1 cells. With this procedure, we demonstrated that the p13suc1-associated cdc2-like histone H1 kinase was activated before cell division at the point of commitment to division in Paramecium. Further, we show that Paramecium cdc2-like proteins occurred principally as monomers and that these monomers were active as histone H1 kinases in vitro.     

The formalization and analysis of a communications protocol

The MSMIE protocol [SBC89] allows processors in a distributed system to communicate via shared memory. It was designed to meet the reliability and efficiency needs of applications such as nuclear safety systems. We present a formal model of the MSMIE protocol expressed in the notation CCS. Desirable properties of the protocol are expressed in the modal mu-calculus, an expressive modal logic. We show that the protocol lacks an important liveness property. In actual operation, additional operating constraints are checked to avoid potential problems. We present a modified protocol and show that it possesses the liveness property even without checking operating constraints. We also show how parts of the analysis were automated with the Concurrency Workbench.     

Model of a miniature pig catheterized for pharmacokinetic and pharmacodynamic studies of anti-infective agents

The purpose of this study was to examine the role of sleep problems in the etiology of nursing caries. Two-hundred mothers of children (104 with nursing caries and 96 caries free) from ages 2 to 4.5 years were surveyed to determine whether difficulty with child sleep and ensuing sleep-associated feeding might be related to the presence of nursing caries. Differences were noted between these two groups regarding: average number of nights the child slept through the night (P < 0.001); total hours of sleep per night (P < 0.05); frequency of night waking episodes (P < 0.01); feeding on demand upon waking (P < 0.01); using a bottle to assist with falling asleep at night (P < 0.001); and feeding in association with nap time (P < 0.001). Differences also were noted in regard to average age of weaning (P < 0.001). Our findings suggest that sleep problems among young children are a behavioral risk factor for night-time bottle use and early childhood caries.