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At least 1,279 records · Page 71Linked to original sources
PubMed1997

Lung volume equipment and infection control. ERS/ATS Workshop Report Series. European Respiratory Society/American Thoracic Society.

As part of the consensus workshop regarding lung volume measurements for the American Thoracic Society and European Respiratory Society, this background paper reviews mechanisms and risks of cross-infection resultant from performing measurements of absolute lung volumes either by body plethysmography, gas dilution, or gas wash-out techniques. Published reports of infection attributable to the performance of lung volume measurements are extremely rare. Nevertheless, because some infectious agents could be transmitted during measurements of lung volumes, and because of widespread concerns both of patients and some medical personnel about the risks of transmission of infections during inspiration from equipment used by other patients, a variety of measures have been advocated to minimize the risks of cross-infection. Workshop participants were divided in opinion about whether such testing does indeed pose significant risk of cross-infection, and also could not agree regarding optimal measures to prevent cross-infection. Although there is conflicting information regarding the efficacy of particulate filters for protecting cross-contamination of downstream equipment and tubing, the author recommends that such filters be used when making lung volume measurements, but only if the filter has acceptably low resistance (e.g. <0.15 kPa x L(-1) x s (1.5 cmH2O x L(-1) x s)), and the measurements are adjusted for the impact of the added resistance and dead space.

Cross Infection↗
PubMed1976

Evaluation of type-specific and non-type-specific pseudomonas vaccine for treatment of pseudomonas sepsis during granulocytopenia.

The protective role of serotype-specific and non-type-specific active immunity against Pseudomonas aeruginosa infection was assessed in granulocytopenic dogs. Dogs were preimmunized with either specific serotype 6 vaccine (SI) or nonspecific serotype 3 vaccine (NSI) and challenged intravenously with 10(7) viable serotype 6 P. aeruginosa during granulocytopenia. Control dogs (C) having insignificant anti-pseudomonas antibody levels were also tested. Results showed: (i) significant increase in survival of SI dogs (P less than 0.05) compared to C and NSI dogs, with no significant difference between C and NSI animals; (ii) lower febrile responses in SI dogs; and (iii) markedly reduced bacteremia in SI dogs compared to C and NSI animals. SI dog sera from survivor animals did not kill the infecting pseudomonas strain in vitro. The study demonstrated that type-specific immunity to P. aeruginosa induced by active immunization is effective in protection against pseudomonas during granulocytopenia and that non-type-specific immunity offers no cross-reactive protection. The findings suggest that the reticuloendothelial system in conjunction with specific immunity constitute an important defense against pseudomonas infections.

Agranulocytosis↗
PubMed2002

Cloning and characterization of Edwardsiella ictaluri proteins expressed and recognized by the channel catfish Ictalurus punctatus immune response during infection.

An Edwardsiella ictaluri expression library was screened for clones expressing antigenic E. ictaluri proteins using anti-E. ictaluri serum, which resulted in the isolation of 32 clones. The clones were partially characterized and 4 were selected for complete analysis. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), 2-dimensional PAGE, Western blotting, and DNA sequencing were used to analyze expressed antigenic proteins and encoded genes. Sequence analysis identified 4 putative open reading frames (ORFs) in the insert of Clone 4d6, which corresponded to antigenic acidic proteins of 55, 20 and 18 kDa expressed by both the clone and E. ictaluri cells. The predicted gene products of these ORFs were similar to several products of the imp locus of Rhizobium leguminosarum bv. trifolii. The imp locus of R. leguminosarum contains 14 genes that encode proteins involved in a putative temperature-dependent protein secretion system. In addition there was significant amino acid identity for a variety of hypothetical proteins from R. solanacearum, Ps. aeruginosa, A. tumefaciens, Y. pestis, and Salmonella typhimurium. Overlapping inserts of Clones 1.4, 5d2, and 5d3 encoded ORFs similar to Escherichia coli partial genes serA and pgk, and complete genes rpiA, iciA, yggE, yggB and fda. These genes encode D-3-phosphoglycerate dehydrogenase (serA), ribose 5-phosphate isomerase (rpiA), a specific inhibitor of chromosomal initiation of replication (iciA), a hypothetical protein (yggE), a protein involved in responses to osmotic stress (yggB), fructose 1,6-bisphosphate aldolase (fda), and phosphoglycerate kinase (pgk). Cloned antigenic E. ictaluri proteins of 33, 27, 35 and 45 kDa appeared to be products of the ORFs similar to yggE, rpiA, iciA, and fda respectively. All the cloned antigenic proteins were recognized by antiserum from catfish that had recovered from enteric septicemia of catfish (ESC), indicating that these antigens are expressed during the infectious process. The cloned antigenic proteins were subsequently evaluated as subunit vaccines for protection against wild-type E. ictaluri. All vaccine treatments were protective against E. ictaluri in catfish, but results were inconclusive due to high levels of cross-reactive protection afforded by the E. coli host strain of the cloning vector.

Animals↗
PubMed1992

Cross-reactivity between Necator americanus and Schistosoma mansoni in mice.

Poly-parasitism is common in endemic communities and reactivity of sera from hookworm-infected patients against schistosomular antigens has been reported. Protective cross-immunity between N. americanus and S. mansoni was investigated in NIH and BALB/c mice. Protective resistance to homologous challenge with both parasites was confirmed in this model, however, functional immunity to heterologous challenge was not demonstrated. Sera from animals which had received homologous challenge with N. americanus and from hookworm-infected mice, which had previously been exposed to radiation-attenuated S. mansoni, exhibited an enhanced IgGAM response to infective stage N. americanus somatic antigens. The implications of these results with respect to serodiagnosis are discussed.

Animals↗
PubMed2002

Lipopolysaccharide preconditioning and cross-tolerance: the induction of protective mechanisms for rat intestinal ileus.

BACKGROUND & AIMS: Endotoxin elicits an inflammatory response within the intestinal muscularis and causes intestinal muscle dysfunction. Our aims were to investigate intestinal muscle recovery after a single or repeated lipopolysaccharide (LPS) injections. We also investigated the ability of LPS to induce cross-tolerance to postoperative ileus. METHODS: Motility was measured in vivo and in vitro by transit and organ-bath techniques. Nuclear factor kappa-B, nuclear factor interleukin 6, and signal transducer and activator of transcription were quantified by using electrophoretic mobility shift assay, and tumor necrosis factor alpha, interleukin 6, inducible nitric oxide synthase, and cyclooxygenase 2 were measured with reverse-transcription polymerase chain reaction. Myeloperoxidase histochemistry for neutrophils was performed in jejunal muscularis whole mounts. RESULTS: Endotoxin-induced suppression of in vitro muscle contractility temporally recovered over 7 days with a similar profile whether after a single dose or during the continuous daily injection of LPS. Functional adaptation to continuous LPS was reflected in a significant blunting of transcription factor activation and cytokine messenger RNA up-regulation compared with the naive LPS-stimulated muscularis. Preconditioning of the muscularis showed significant cross-tolerance to the functional, molecular, and leukocytic sequelae of intestinal manipulation. CONCLUSIONS: The muscularis externa recovered and developed tolerance to endotoxin over 7 days, which conferred cross-tolerance to intestinal manipulation. Thus, preconditioning induces protective mechanisms to a subsequent insult within the muscularis externa.

Animals↗
PubMed2006

Induction of cross-reactive immune responses to NTS-DBL-1alpha/x of PfEMP1 and in vivo protection on challenge with Plasmodium falciparum.

The interactions of Plasmodium falciparum infected erythrocytes parasitized red blood cells (pRBC) with endothelial receptors and erythrocytes are mediated by multiple Duffy-binding like (DBL) and cysteine-rich interdomain region (CIDR) domains harboured in the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). The success of a subunit vaccine based on PfEMP1 depends on its ability to elicit cross-reactive responses to a substantial number of PfEMP1 variants. We have here evaluated serological PfEMP1 cross-reactivity by immunizing rats with phylogenetically diverse recombinant NTS-DBL-1alpha/x fusion domains from the 3D7 genome parasite emulsified in Montanide ISA 720. Cross-reactivity was elicited to these diverse DBL-1alpha/x domains as measured by ELISA and by immunoblotting. Employing a novel in vivo model of human infected erythrocyte sequestration, immunized animals were challenged with the FCR3S1.2 clone and cross-protection in terms of reduction in lung sequestration amounting to approximately 50% was demonstrated. Our results suggest that immunization with phylogenetically distant DBL-1alpha/x variants, can elicit partial cross-protection to challenge with the parasites harbouring a distant variant. These observations have implications for the design of multi-component vaccines against P. falciparum malaria.

Animals↗
PubMed1985

Protection against fatal Pseudomonas aeruginosa sepsis by immunization with smooth and rough lipopolysaccharides.

The protective capacity of various native and mutant lipopolysaccharide antigens against fatal Pseudomonas aeruginosa burn wound sepsis was evaluated. Immunization with O-polysaccharide-deficient lipopolysaccharides derived from Escherichia coli J5 or Salmonella typhi Ty 21a afforded substantial protection against only one of five Pseudomonas aeruginosa challenge strains of various serotypes. Immunization with both lipopolysaccharide antigens evoked antibody of the immunoglobulin G class which recognized lipopolysaccharide isolated from the challenge strain against which protection was noted. This was not seen for the remaining four challenge strains. Attempts to demonstrate cross-serotype protection using O-antigen-deficient and core-deficient Pseudomonas aeruginosa lipopolysaccharide antigens was, for the most part, unsuccessful. In contrast, high levels of protection against all six serotypes of challenge strains were seen following immunization with homologous lipopolysaccharide.

Animals↗
PubMed2006

Vaginal protection and immunity after oral immunization of mice with a novel vaccine strain of Listeria monocytogenes expressing human immunodeficiency virus type 1 gag.

Natural transmission of human immunodeficiency virus (HIV) occurs at mucosal surfaces. During acute infection, intestinal and other mucosae are preferential sites of virus replication and rapidly become depleted of CD4(+) T cells. Therefore, mucosal immunity may be critical to control both initial infection and the massive early spread of virus. An attenuated D-alanine-requiring strain of the oral intracellular microorganism Listeria monocytogenes expressing HIV type 1 gag was shown to induce protective cell-mediated immunity in mice against viruses that express HIV gag when immunization occurs in the presence of a transient supply of D-alanine. In this study, we examined the efficacy of new attenuated strains that are able to synthesize d-alanine from a heterologous dal gene tightly regulated by an actA-promoted resolvase recombination system. In the absence of d-alanine, Gag-specific cytotoxic T lymphocytes (CTLs) were induced systemically after intravenous immunization, and one strain, Lmdd-gag/pARS, induced strong dose-dependent Gag-specific CTLs after oral immunization. A significant level of Gag-specific CD8(+) T cells was induced in the mucosal-associated lymphoid tissues (MALTs). Upon intravaginal challenge of these orally immunized mice with recombinant vaccinia virus (rVV) expressing HIV gag, gamma interferon- and tumor necrosis factor alpha-secreting Gag-specific CD8(+) T cells were dramatically increased in the spleen and MALTs. Oral immunization with Lmdd-gag/pARS led to complete protection against vaginal challenge by a homologous clade B gag-expressing rVV. In addition, strong cross-clade protection was seen against clades A and C and partial protection against clade G gag-expressing rVV. These results suggest that Lmdd-gag/pARS may be considered as a novel vaccine candidate for use against HIV/AIDS.

Administration, Oral↗
PubMedDate not supplied

[The tissue specificity of the protective action of cytoplasmic factors on the membrane-bound system of Ca2+ transport in the sarcoplasmic reticulum of the heart and the skeletal muscles].

Whether soluble cytoplasmic factors (SCF) can protect the membrane-associated Ca2+ transport system in sarcoplasmic reticulum (SR) was studied in controls, stress and adaptation to it. Ca-transport was damaged in stress much more in the skeletal muscles compared to the heart. Initial performance of Ca-pump in the skeletal muscles was decreased by 43%, in the heart--no change. After stress, thermoresistance of the enzyme in the skeletal muscles was 3-5 times less than in the myocardium. The enzyme reaction on adaptation and stress in both tissues is the same--a significant rise in Ca-pump thermoresistance. When preadapted animals are exposed to stress, deceleration of the initial speed and resistance of the enzyme in the myocardium are fully prevented while in the skeletal muscles Ca-pump resistance is higher than in the controls. In the heart, SCF have a protective effect on thermoresistance. In the skeletal muscles, SCF protect initial speed of the enzyme in the control, in stress and adaptation to it. A cross-over protective SCF (from adapted animals) effect was found on the stress-impaired membrane system of Ca-transport. Adapted SCF elevate 2.5-fold thermoresistance of the enzyme. Correlation between cytoplasmic and membrane protective mechanisms in stress and adaptation to it is considered.

Acute Disease↗
PubMed1983

Cross-resistance to fecal excretion of Yersinia enterocolitica in mice by oral vaccination of killed cells.

Mice vaccinated orally with heat-killed cells of serovar O3 of Yersinia enterocolitica were protected only against fecal excretion of the homologous serovar, whereas Formalin-killed cells provided cross-protection against serovar O9 and vice versa. Serovar IVA of Yersinia pseudotuberculosis, when Formalin-killed, also provided cross-protection against Y. enterocolitica. On the other hand, Serratia liquefaciens and serovar O6 strains did not furnish cross-protection.

Animals↗
PubMed1995

Protection against morbillivirus-induced encephalitis by immunization with a rationally designed synthetic peptide vaccine containing B- and T-cell epitopes from the fusion protein of measles virus.

Synthetic peptides representing T- and B-cell epitopes from the fusion (F) protein of measles virus (MV) were tested for their ability to induce a protective immune response against intracerebral challenge with neuroadapted strains of MV and canine distemper virus (CDV) in mice. Of the panel of peptides tested, only a chimeric peptide consisting of two copies of a promiscuous T-cell epitope (representing residues 288 to 302 of MV F protein) synthesized at the amino terminus of a B-cell epitope (representing residues 404 to 414 of MV F protein) was able to induce a protective response against challenge with MV and CDV in inbred mice. The protective response induced by this peptide (TTB) was associated with a significant reduction in mortality, histological absence of acute encephalitis, and greatly reduced titers of virus in the brains of TTB-immune mice following challenge compared with the results for nonimmunized controls. A chimeric peptide comprising one copy of the T-cell epitope and one copy of the B-cell epitope (TB) did not induce a protective response. A comparison of the antibody responses induced by the two chimeras suggested that differences in protective efficacy following immunization may be a result of the higher affinity of the antibody induced by the TTB peptide than that of the antibody induced by the TB peptide. In addition, differences in the immunoglobulin G subclass of the antipeptide antibody responses were observed, and these may play a role in the differences in protection observed. These results indicate that appropriately designed synthetic peptides have potential as vaccines for the induction of cross-reactive protection against morbilliviruses.

Amino Acid Sequence↗
PubMed2001

The molecular revolution in the development of vaccines against ectoparasites.

Over the last decade, the application of a spectrum of molecular techniques has begun to revolutionise our understanding of protective immune responses to ectoparasites and the targets for those responses. The catalogue of potential and actual protective antigens characterised in detail is slowly expanding. The validity of regarding such antigens as generic and capable of cross-species protection is being explored. The immune interactions between host and parasite are being studied at a molecular rather than cellular level. All this should contribute to the eventual development of a range of recombinant vaccines, though important scientific limitations remain. These range from the innate susceptibility of individual parasite species to immunological attack, which can only be assessed on a case by case basis, to our ability to produce the desired recombinant antigens and to elicit and maintain the necessary immunological responses.

Animals↗
PubMed2000

Immobilization of BINOL by cross-linking copolymerization of styryl derivatives with styrene, and applications in enantioselective Ti and Al Lewis acid mediated additions of Et2Zn and Me3SiCN to aldehydes and of diphenyl nitrone to enol ethers

The chiral ligand 1,1'-bi-2-naphthol (BINOL) has been succesfully immobilized on polystyrene. Several dendritic and non-dendritic BINOL derivatives (3, and 13-17), bearing at least two polymerizable styryl groups, were prepared and fully characterized. Suspension copolymerization of the MOM- or TIPS-protected cross-linking BINOL ligands (MOM = methyloxymethyl, TIPS = triisopropylsilyl) with styrene, cleavage of the protecting-groups, and loading with a Lewis-acid afforded catalytically active polystyrene-supported BINOLates. The polymer-bound BINOLs p-3, and p-13-p-16 were tested in the Ti-BINOLate-mediated addition of Et2Zn to PhCHO. The enantioselectivities (up to 93%) and conversions obtained with the polymer-bound catalysts were in most cases identical (within experimental error) to those obtained with the unsubstituted 1,1'-bi-2-naphthol and with the non-polymerized BINOL cross-linkers under homogeneous conditions. Special focus was put on the reusability of the supported catalyst: the polymer-beads were used in up to 20 consecutive catalytic runs, with the best polymers showing no or only minor loss of selectivity. BINOL-polymers p-17, obtained by copolymerization of a 3,3'-distyryl-substituted BINOL 17a with styrene, were used in the BINOL. AlMe-mediated cycloaddition of diphenyl nitrone with alkyl vinyl ethers. In all cases the exo/endo selectivity (> or =92:8) and the enantioselectivities with which the exo-cycloadducts were formed (> or =95%) correspond to those observed in the homogeneous reactions. A dendritically cross-linked BINOL-polymer was also employed in the Ti-BINOLate-mediated cyanosilylation of pivalaldehyde. The enantiopurity of the cyanohydrine obtained in the first run was as high as in the homogeneous reaction (72%); surprisingly the catalytic performance of the supported catalyst increased steadily during the first catalytic cycles to reach 83%. Thus, cross-linking BINOLs can be succesfully incorporated into a polystyrene matrix (without racemization!) to give polymer-bound BINOL ligands that give excellent performance over many catalytic cycles with catalytic activities comparable with those of soluble analogues.

Journal Article↗
PubMed2004

Protective immunization against group B meningococci using anti-idiotypic mimics of the capsular polysaccharide.

Use of the serogroup B meningococcal capsular polysaccharide (MenB CP) as a vaccine is hampered by the presence of epitopes that cross-react with human polysialic acid. As non-cross-reactive, protective capsular epitopes have also been described, we set out to develop protein mimics of one of such epitopes using as a template a highly protective mAb (mAb Seam 3) raised against a chemically modified form of the MenB CP (N-Pr MenB CP). Using phage display, anti-idiotypic single-chain Ab fragments (scFvs) were obtained from spleen cells of mice immunized with the Seam 3 mAb. Two Seam 3-specific scFvs competed with N-Pr MenB CP for binding to either mAb Seam 3 or rabbit Abs present in typing sera. Moreover, in mice and rabbits the scFvs elicited the production of Abs reacting with both N-Pr MenB CP and whole meningococci, but not with human polysialic acid. These scFv-induced Ab responses were boostable and of the Th1 type, as shown by a predominance of IgG2a. In addition, passive immunization with sera from scFv-immunized animals partially protected neonatal mice from experimental infection with group B meningococci. In conclusion, we have produced anti-idiotypic scFvs that mimic a protective MenB CP epitope and may be useful in the development of an alternative group B meningococcal vaccine.

Animals↗
PubMedDate not supplied

[The protective effect of preliminary adaptation to the stress from disorders of the gas-transport function of the blood in hemorrhagic shock].

To prevent disturbances of blood gas-transport function in hemorrhagic shock, we used cross-over protective effect of adaptation to short-term immobilization stress. Adaptation of rats to stress was associated with a rise in baseline arterial blood, pH in venous blood; fall in PO2, PCO2,P50. Stress-adapted rats appeared more resistant to blood loss. Gas transport 1 hour after hemorrhage was better than in non-adapted animals demonstrated more active compensatory reactions in l low hypoxic damage to the tissues. 2.5-h survival after start of bleeding in control animals made up 35%, in the group of adapted animals--67%. Thus, adaptation to short-term immobilization stress is a non-pharmacological method to prevent hemorrhagic shock.

Adaptation, Physiological↗
PubMed2004

Dendritic cells induce immunity and long-lasting protection against blood-stage malaria despite an in vitro parasite-induced maturation defect.

Dendritic cells (DC) suffer a maturation defect following interaction with erythrocytes infected with malaria parasites and become unable to induce protective malaria liver-stage immunity. Here we show that, by contrast, maturation-arrested DC in vitro are capable of the successful induction of antigen-specific gamma interferon (IFN-gamma) and interleukin 4 (IL-4) T-cell responses, antibody responses, and potent protection against lethal blood-stage malaria challenge in vivo. Similar results were found with DC pulsed with intact parasitized Plasmodium yoelii or Plasmodium chabaudi erythrocytes. Cross-strain protection was also induced. High levels of protection (80 to 100%) against lethal challenge were evident from 10 days after a single immunization and maintained up to 120 days. Interestingly, correlation studies versus blood-stage protection at different time points suggest that the immune effector mechanisms associated with protection could change over time. Antibody-independent, T-cell- and IL-12-associated protection was observed early after immunization, followed by antibody and IL-4-associated, IFN-gamma-independent protection in long-term studies. These results indicate that DC, even when clearly susceptible to parasite-induced maturation defect effects in vitro, can be central to the induction of protection against blood-stage malaria in vivo.

Animals↗