Immobilization of biocatalysts in thermogels using the resonance nozzle for rapid drop formation and an organic solvent for gelling

Summary The resonance nozzle immobilization technique was tested with thermo-hardening hydrogels (agar, gellan and -carrageenan) and compared with the conventional needle technique. After nozzling the warm gel solution, the formed droplets were caught in an ice-cold two-phase system consisting of an organic solvent (n-butylacetate, hexane or nonane) as top phase, in which gelling occurred, and aqueous medium as bottom phase. The cells used were yeast cells (Saccharomyces cerevisiae), bacterial cells (Mycobacterium aurum L1), plant cells (Tagetes minuta) and insect cells (Spodoptera frugiperda). The retention of the respiration activity was used as a criterion for the suitability of the conditions applied. The relatively polar solvent n-butylacetate with the low log P value gave the poorest activity retention, which is in agreement with experimentally validated theory. For all gels, the resonance nozzle technique proved to give satisfactory results, although the retention of respiration activity was generally lower than obtained with the needle technique.     

Live attenuated pseudorabies virus expressing envelope glycoprotein E1 of hog cholera virus protects swine against both pseudorabies and hog cholera

To investigate whether live attenuated pseudorabies virus (PRV) can be used as a vaccine vector, PRV recombinants that expressed envelope glycoprotein E1 of hog cholera virus (HCV) were generated. Pigs inoculated with these recombinants developed high levels of neutralizing antibodies against PRV and HCV and were protected against both pseudorabies and hog cholera (classical swine fever).     

Phylogenetic diversification of immunoglobulin genes and the antibody repertoire

Immunoglobulins are encoded by a large multigene system that undergoes somatic rearrangement and additional genetic change during the development of immunoglobulin-producing cells. Inducible antibody and antibody-like responses are found in all vertebrates. However, immunoglobulin possessing disulfide-bonded heavy and light chains and domain-type organization has been described only in representatives of the jawed vertebrates. High degrees of nucleotide and predicted amino acid sequence identity are evident when the segmental elements that constitute the immunoglobulin gene loci in phylogenetically divergent vertebrates are compared. However, the organization of gene loci and the manner in which the independent elements recombine (and diversify) vary markedly among different taxa. One striking pattern of gene organization is the "cluster type" that appears to be restricted to the chondrichthyes (cartilaginous fishes) and limits segmental rearrangement to closely linked elements. This type of gene organization is associated with both heavy- and light-chain gene loci. In some cases, the clusters are "joined" or "partially joined" in the germ line, in effect predetermining or partially predetermining, respectively, the encoded specificities (the assumption being that these are expressed) of the individual loci. By relating the sequences of transcribed gene products to their respective germ-line genes, it is evident that, in some cases, joined-type genes are expressed. This raises a question about the existence and/or nature of allelic exclusion in these species. The extensive variation in gene organization found throughout the vertebrate species may relate directly to the role of intersegmental (V<==>D<==>J) distances in the commitment of the individual antibody-producing cell to a particular genetic specificity. Thus, the evolution of this locus, perhaps more so than that of others, may reflect the interrelationships between genetic organization and function.      

Treatment of Helicobacter pylori Infection: A Review of the World Literature

Background. None of the currently used anti- Helicobacter pylori drug regimens cures the infection 100%, and cure results still vary considerably. The present article reviews the effectiveness of currently used antimicrobial regimens, aimed to cure H. pylori infection.
Methods. Data collection started from the beginning of the anti- H. pylori -therapy era until May 1995. No attempt at formal metanalysis has been made, because many studies have been published only in abstract form. Attempts were made to exclude duplicates of studies by comparison to previously reported ones; the authors of suspected duplicates were contacted. After amalgamation of the number of included patients and the number of successfully treated patients, the mean values of eradication rates and the 95% confidence intervals were calculated.
Results. A total of 237 treatment arms were analyzed. Bismuth triple therapy continues to reach high eradication rates worldwide (78–89%). Side effects leading to diminished patient compliance and the marked decline of eradication efficacy in cases of metronidazole resistance are considered to be the major drawbacks of this therapy. Proton pump inhibitor (PPI) dual therapy is better tolerated with fewer side effects than is bismuth triple therapy. The mean eradication rates vary from 55 to 75%, and the extremes lie between 24 and 93%. PPI triple therapies have been shown to be very effective against H. pylori (eradication rates, 80–89%). Quadruple therapy leads to a mean eradication rate of 96%.
Conclusion. Based on efficacy, PPI triple or bismuth triple therapy are recommended as first-line treatment for H. pylori infection. Quadruple therapy could serve as second-line treatment for eradication of initial failures and in case of metronidazole resistance.     

Fascioloides magna (Bassi, 1875) in feral swine from southern Texas.

Between 1971 and 1975, Fascioloides magna was found in 46 of 67 (69%) feral swine (Sus scrofa) in southern Texas. Flukes were recovered from swine in areas where F. magna commonly has been recovered from white-tailed deer and cattle. One to 12 flukes were recovered from each infected animal. Their presence was indicated by black hematin pigment on the liver and various other internal organs. Eggs were not detected in the gallbladder or feces of infected animals although mature flukes and eggs were recovered in the livers suggesting that, like cattle, feral swine can be infected but are aberrant hosts for the parasite and do not disseminate eggs.     

Why genetic selection to reduce the prevalence of infectious diseases is way more promising than currently believed

Genetic selection for improved disease resistance is an important part of strategies to combat infectious diseases in agriculture. Quantitative genetic analyses of binary disease status, however, indicate low heritability for most diseases, which restricts the rate of genetic reduction in disease prevalence. Moreover, the common liability threshold model suggests that eradication of an infectious disease via genetic selection is impossible because the observed-scale heritability goes to zero when the prevalence approaches zero. From infectious disease epidemiology, however, we know that eradication of infectious diseases is possible, both in theory and practice, because of positive feedback mechanisms leading to the phenomenon known as herd immunity. The common quantitative genetic models, however, ignore these feedback mechanisms. Here, we integrate quantitative genetic analysis of binary disease status with epidemiological models of transmission, aiming to identify the potential response to selection for reducing the prevalence of endemic infectious diseases. The results show that typical heritability values of binary disease status correspond to a very substantial genetic variation in disease susceptibility among individuals. Moreover, our results show that eradication of infectious diseases by genetic selection is possible in principle. These findings strongly disagree with predictions based on common quantitative genetic models, which ignore the positive feedback effects that occur when reducing the transmission of infectious diseases. Those feedback effects are a specific kind of Indirect Genetic Effects; they contribute substantially to the response to selection and the development of herd immunity (i.e., an effective reproduction ratio less than one).     

Equilibrium-Phase High Spatial Resolution Contrast-Enhanced MR Angiography at 1.5T in Preoperative Imaging for Perforator Flap Breast Reconstruction

Objectives

The aim was (i) to evaluate the accuracy of equilibrium-phase high spatial resolution (EP) contrast-enhanced magnetic resonance angiography (CE-MRA) at 1.5T using a blood pool contrast agent for the preoperative evaluation of deep inferior epigastric artery perforator branches (DIEP), and (ii) to compare image quality with conventional first-pass CE-MRA.

Methods

Twenty-three consecutive patients were included. All patients underwent preoperative CE-MRA to determine quality and location of DIEP. First-pass imaging after a single bolus injection of 10 mL gadofosveset trisodium was followed by EP imaging. MRA data were compared to intra-operative findings, which served as the reference standard.

Results

There was 100% agreement between EP CE-MRA and surgical findings in identifying the single best perforator branch. All EP acquisitions were of diagnostic quality, whereas in 10 patients the quality of the first-pass acquisition was qualified as non-diagnostic. Both signal- and contrast-to-noise ratios were significantly higher for EP imaging in comparison with first-pass acquisitions (p<0.01).

Conclusions

EP CE-MRA of DIEP in the preoperative evaluation of patients undergoing a breast reconstruction procedure is highly accurate in identifying the single best perforator branch at 1.5Tesla (T). Besides accuracy, image quality of EP imaging proved superior to conventional first-pass CE-MRA.     

Molecular shape of the cationic lipid controls the structure of cationic lipid/dioleylphosphatidylethanolamine-DNA complexes and the efficiency of gene delivery

Pyridinium amphiphiles, abbreviated as SAINT, are highly efficient vectors for delivery of DNA into cells. Within a group of structurally related compounds that differ in transfection capacity, we have investigated the role of the shape and structure of the pyridinium molecule on the stability of bilayers formed from a given SAINT and dioleoylphosphatidylethanolamine (DOPE) and on the polymorphism of SAINT/DOPE-DNA complexes. Using electron microscopy and small angle x-ray scattering, a relationship was established between the structure, stability, and morphology of the lipoplexes and their transfection efficiency. The structure with the lowest ratio of the cross-sectional area occupied by polar over hydrophobic domains (SAINT-2) formed the most unstable bilayers when mixed with DOPE and tended to convert into the hexagonal structure. In SAINT-2-containing lipoplexes, a hexagonal topology was apparent, provided that DOPE was present and complex assembly occurred in 150 mm NaCl. If not, a lamellar phase was obtained, as for lipoplexes prepared from geometrically more balanced SAINT structures. The hexagonal topology strongly promotes transfection efficiency, whereas a strongly reduced activity is seen for complexes displaying the lamellar topology. We conclude that in the DOPE-containing complexes the molecular shape and the nonbilayer preferences of the cationic lipid control the topology of the lipoplex and thereby the transfection efficiency.     

IL-11 and IL-11Rα immunolocalisation at primate implantation sites supports a role for IL-11 in placentation and fetal development

Embryo implantation, endometrial stromal cell decidualization and formation of a functional placenta are critical processes in the establishment and maintenance of pregnancy. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus and IL-11 promotes decidualization in the human. IL-11 action is mediated via binding to the specific IL-11 receptor α (IL-11Rα). The present study examined immunoreactive IL-11 and IL-11Rα in cycling rhesus monkey endometrium, at implantation sites in cynomolgus and rhesus monkeys and in human first trimester decidua and defined distinct spatial and temporal patterns. In cycling rhesus monkey endometrium, IL-11 and IL-11Rα increased in both basalis and functionalis regions during the secretory compared with the proliferative phase, with changing cellular locations in luminal and glandular epithelium and stroma. The patterns were similar overall to those previously described in human endometrium. Differences were seen in immunostaining during implantation in cynomologus and rhesus monkey. In the cynomolgus, very little staining for IL-11 or IL-11Rα was seen in syncytio- and cyto-trophoblast cells in the villi between days 12 and 150 of pregnancy although there was moderate staining in cytotrophoblast in the shell between days 12 and 17 and in subpopulations of cytotrophoblast cells invading the arteries at day 17. By contrast in the rhesus monkey between days 24 and 35 of pregnancy and in human first trimester placenta, cyto- and syncytio-trophoblast in the villi but not cytotrophoblast in the shell were positively stained. The most intense staining for both IL-11 and IL-11Rα was present within the decidua in the maternal component of implantation sites in all three primates but moderate staining was also present in maternal vascular smooth muscle and glands perivascular cells and epithelial plaques. These results are consistent with a role for IL-11 both during decidualization and placentation in primates.     

Direct visualization of dynamic protein-DNA interactions with a dedicated atomic force microscope.

Photolyase DNA interactions and the annealing of restriction fragment ends are directly visualized with the atomic force microscope (AFM). To be able to interact with proteins, DNA must be loosely bound to the surface. When MgCl2 is used to immobilize DNA to mica, DNA is attached to the surface at distinct sites. The pieces of DNA in between are free to move over the surface and are available for protein interaction. After implementation of a number of instrumental improvements, the molecules can be visualized routinely, under physiological conditions and with molecular resolution. Images are acquired reproducibly without visible damage for at least 30 min, at a scan rate of 2 x 2 microm2/min and a root mean square noise of less than 0.2 nm. Nonspecific photolyase DNA complexes were visualized, showing association, dissociation, and movement of photolyase over the DNA. The latter result suggests a sliding mechanism by which photolyase can scan DNA for damaged sites. The experiments illustrate the potential that AFM presents for modern molecular biology.