[The protecting sign of the Red-Cross at the front line].
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Humans↗
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Results for “Cross Protection”
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[Signal-crossing station uncoupler, an apparatus for protection from electrical accidents in medical facilities].
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Computers↗
Poor sanitation and helminth infection protect against skin sensitization in Vietnamese children: A cross-sectional study.
BACKGROUND: Geohelminth infection and poor hygiene may be protective against allergic sensitization. OBJECTIVE: To determine whether current helminth infection is associated with a reduced prevalence of allergen skin test sensitization in a Southeast Asian population of children with a high prevalence of hookworm infection. METHODS: A total of 1742 Vietnamese schoolchildren were invited to take part in a cross-sectional survey. Allergen skin sensitization to house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae) and American cockroach (Periplaneta americana) were measured and stool samples for qualitative and quantitative geohelminth estimation collected. RESULTS: A total of 1601 children age 6 to 18 participated. Sensitization to dust mites was present in 14.4% and to cockroach in 27.6% of children. In a mutually adjusted model, the risk of sensitization to dust mites was reduced in those with higher hookworm burden (adjusted odds ratio [OR] for 350+ vs no eggs per gram, 0.61; 95% CI, 0.39-0.96) and with Ascaris infection (adjusted OR, 0.28; 0.10-0.78), and increased in those using flush toilets (adjusted OR for flush toilet vs none/bush/pit, 2.51; 1.00-6.28). In contrast, sensitization to cockroach was not independently related to geohelminth infection but was increased in those regularly drinking piped or well water rather than from a stream (adjusted OR, 1.33; 1.02-1.75). CONCLUSION: Geohelminth infection, sanitation, and water supply influence the risk of allergic sensitization in Vietnamese children. This is consistent with a protective effect against allergy by geohelminth or other gastrointestinal infection. CLINICAL IMPLICATIONS: If the inverse relationship between geohelminth infection, poor sanitation, and allergic sensitization proves to be causal, drugs derived from parasite products may help to alleviate clinical allergic disease.
Adolescent↗
The superiority of aortic cross-clamping with profound local hypothermia for myocardial protection during aorta-coronary bypass grafting.
Two different operative techniques for aorta-coronary bypass grafting were utilized in two comparable groups of patients. In one group (155 patients) distal anastomoses were carried out with the aorta cross-clamped and myocardial protection provided by profound local hypothermia (clamped group). In a second group (149 patients) distal anastomoses were carried out with the aorta unclamped and the left ventricle fibrillating and vented (unclamped group). Mortality rates were similar in the two groups (0.6 per cent in clamped group versus 1.3 per cent in unclamped group). The incidence of perioperative infarction was 15 per cent in the unclamped group and 8 per cent in the clamped group (p less than 0.05). Postoperative serum glutamic oxaloacetic transaminase (SGOT) and lactic dehydrogenase (LDH) levels were significantly higher for the first 4 postoperative days in the unclamped group than in the clamped group. Hemodynamic studies in a subset of each group revealed no important differences in left ventricular function in the immediate postoperative period. The data demonstrate that in patients undergoing aorta coronary bypass grafting, performance of distal anastomoses with aortic cross-clamping and profound local hypothermia results in less intraoperative myocardial injury than performance of distal anastomoses in the perfused, fibrillating, and vented left ventricle.
Aspartate Aminotransferases↗
Overview of nuclear fragmentation models and needs.
It has been known for some time that adequate assessment of spacecraft shield requirements and concomitant estimates of astronauts radiation exposures from galactic cosmic radiation requires accurate, quantitative methods for characterizing these radiation fields as they pass through thick absorbers. The main nuclear interaction processes involved are (1) nuclear elastic and inelastic collisions, and (2) nuclear breakup (fragmentation) and electromagnetic dissociation (EMD). Nuclear fragmentation and EMD are important because they alter the elemental and isotopic composition of the transported radiation fields. At present, there is no suitably accurate theory for predicting nuclear fragmentation cross sections for all collision pairs and energies of interest in space radiation protection. Typical cross-section differences between theory and experiment range from about 25 percent to a factor of two. The resulting errors in transported flux, for high linear energy transfer (LET) particles, are comparble to these cross-section errors. In this overview, theoretical models of heavy ion fragmentation currently used to generate input data bases for cosmic-ray transport and shielding codes are reviewed. Their shortcomings are discussed. Further actions needed to improve their accuracy and generality are presented.
Cosmic Radiation↗
Glutaraldehyde cross-linking of lectins to marker enzymes: protection of binding site by specific sugars.
The role of bound specific sugars in protecting the sugar binding activity of several galactose binding proteins during their covalent conjugation to horse radish peroxidase by glutaraldehyde-mediated cross-linking was examined by: a) affinity matrix binding of the conjugate, b) enzyme linked lectin assay and c) hemagglutination assay. During conjugation using 1% glutaraldehyde, protection of jack fruit (Artocarpus integrifolia) lectin (jacalin) activity depended on concentration of specific sugar present during conjugation; optimum protection was offered by 50 mM galactose. This indicated the presence of one or more primary groups at the binding site of jacalin, which is (are) essential for sugar binding. On the other hand, such essential amino group(s) was not indicated at the sugar binding site of the peanut lectin, bovine heart galectin or of the human serum anti alpha-galactoside antibody, since exclusion of sugar during their conjugation to HRP did not diminish sugar binding activity. The differential behavior is discussed in the light of reported differences in sugar specificities. Results indicated that sugar mediated blocking of active site may be used in characterization of the latter in lectins.
Animals↗
Injuries to riders in the cross country phase of eventing: the importance of protective equipment.
OBJECTIVES: To determine the distribution of injuries in the eventing discipline of equestrian sports and the effectiveness of the protective equipment worn. METHODS: Data on all injuries sustained in the cross country phase over fixed obstacles were collected from 54 days of competition from 1992 to 1997. This involved 16,940 rides. RESULTS: Data on a total of 193 injuries were collected, which included two deaths. This represents an injury rate of 1.1%. Head and facial injuries represented the largest group (31%), with one third of these requiring treatment in hospital. All riders were wearing protective helmets and body protectors. CONCLUSIONS: Eventing is one of the most dangerous equestrian sports. Improved protective equipment, which is mandatory for 1999, should reduce the severity of these injuries.
Animals↗
Relationship of structure to function in bacterial endotoxins: serologically cross-reactive components and their effect on protection of mice against some gram-negative infections.
Rabbit antisera were prepared against the heptoseless Re mutants, Salmonella minnesota R595 and S. typhimurium SLI102, as well as against purified R595 glycolipid coated on autologous erythrocytes. The antisera cross-reacted with the endotoxic glycolipids extracted from Re mutants of various bacterial strains, including S. minnesota R595, S. typhimurium SLI102, Escherichia coli D3Im4, E. coli D2If2 and E. coli F515, as shown by passive haemagglutination and gel diffusion tests. The anti-Re sera also cross-reacted with the RESI preparations (a purified 'lipid A' fraction) from the endotoxic lipopolysaccharides of various heterologous smooth Gram-negative bacteria including Serratia marcescens. Psuedomonas fluorescens and E. coli 0127. However, the same antisera failed to protect mice against infection by Gram-negative bacteria such as Klebsiella pneumoniae type II, S. typhi 0901, P. aeruginosa 119 and E. coli. The results suggest that although the lipid moieties of the lipopolysaccharides in the cell wall of Gram-negative bacteria share cross-reactive immunodeterminant groups, these groups may not be accessible to antibody against them.
Animals↗
A comparison between ischemic preconditioning, intermittent cross-clamp fibrillation and cold crystalloid cardioplegia for myocardial protection during coronary artery bypass graft surgery.
The aim of this study was to compare ischemic preconditioning (IPC) with two established methods of myocardial protection, namely cold crystalloid cardioplegia and intermittent cross-clamp fibrillation (ICCF), in coronary artery bypass graft (CABG) surgery. This was a prospective randomised study. Thirty CABG patients were randomised to receive: (a) St Thomas' cardioplegia solution no. 2; (b) ICCF; or (c) IPC (two 3-min periods of ischemia with 2-min of reperfusion). Surgery was performed under standardised conditions by one surgeon (WBP). The primary endpoint was cardiac troponin T release during the first 72 h after surgery. Mean troponin T at 72 h was significantly lower in the IPC group (0.5 microg/l; p=0.05, ANOVA) compared with the cardioplegia and ICCF groups (2.1 and 1.3 microg/l respectively). This suggests that ischemic preconditioning is superior at limiting myocardial necrosis during CABG, but there is no difference between cold crystalloid cardioplegia and intermittent cross-clamp fibrillation.
Aorta, Thoracic↗
Lack of cross-immunity among Pasteurella multocida type A strains.
Active and passive protection studies in mice using sheep antisera revealed that the immunological relationship among Pasteurella multocida Type A strains could not be correlated with their serological relationship as determined by a haemagglutination or an agglutination test. Furthermore, strains possessing similar phenol extractable antigens or heat stable antigens did not provide complete cross-protection. The conclusion was reached that immunity to P. multocida Type A strains is induced by an antigen which is strain specific and not detectable by existing serological typing systems. The immunological relationship of strains can therefore not be predicted on the basis of their serological characteristics.
Animals↗
Roles of the Maltese cross form in the development of parasitemia and protection against Babesia microti infection in mice.
Babesia microti, a hemoprotozoan parasite of rodents, is also important as a zoonotic agent of human babesiosis. The Maltese cross form, which consists of four masses in an erythrocyte, is characteristic of the developmental stage of B. microti. Monoclonal antibody (MAb) 2-1E, which specifically recognizes the Maltese cross form of B. microti, has been described previously. In the present study, we examined the roles of the Maltese cross form during the infectious course of B. microti in mice. The number of the Maltese cross form increased in the peripheral blood of infected mice prior to the peak of parasitemia. With confocal laser scanning microscopy, MAb 2-1E was found to be reactive with the ring form, with the parasites undergoing transformation to the Maltese cross form and subsequent division, and also with extracellular merozoites. Furthermore, the Maltese cross form-related antigen (MRA) gene was isolated from a B. microti cDNA library by immunoscreening with MAb 2-1E, and the nucleotide sequence was determined. Genomic analyses indicated that the MRA gene exists as a single-copy gene in B. microti. Immunization of mice with recombinant MRA induced significant protective immunity against B. microti infection. These findings indicate that the Maltese cross form plays important roles in both the development of parasitemia and the protective response against the infection.
Amino Acid Sequence↗
Heme-mediated reactive oxygen species toxicity to retinal pigment epithelial cells is reduced by hemopexin.
Catalysis of the formation of reactive oxygen species (RO2S) by low molecular weight complexes of iron has been implicated in several pathological conditions in the retina since photoreceptors and retinal pigment epithelial cells are likely to be especially sensitive to RO2S. Since protective proteins cannot cross the blood-retinal barrier, it is likely that the retina performs its own protective functions by synthesizing proteins that bind iron and nonprotein iron complexes, the major catalysts of RO2S generation. Investigations were carried out to determine whether pigment epithelial cells are themselves sensitive to iron-generated RO2S and whether apo-transferrin and apo-hemopexin, known to be made locally in the retina, can perform a protective function. In 51Cr release assays, the toxicity of exogenous RO2S including hydrogen peroxide or superoxide (generated by xanthine oxidase/hypoxanthine) to human retinal pigment epithelial cells was inhibited by the iron chelators, desferrioxamine and apo-transferrin. Free but not protein-bound ferric iron and heme exacerbated the toxic effect. The toxic effect of heme was abolished by the heme-scavenging, extracellular antioxidant, apo-hemopexin, and also by exogenous bovine serum albumin. In addition, heme toxicity was inhibited by a 3 h preincubation of cells with either heme, apo-hemopexin, or heme-hemopexin 24 h prior to the toxicity assay. It is concluded, first, that toxic effects of iron and heme can be prevented by apo-transferrin or apo-hemopexin and, second, that exposure of RPE cells to free heme or hemopexin sets in motion a series of biochemical events resulting in protection against oxidative stress. It is probable that these include heme oxygenase induction.
Antioxidants↗
Thermal inactivation kinetics of penicillin G acylase obtained from a mutant derivative of Escherichia coli ATCC 11105.
Thermal inactivation kinetics of native and glutaraldehyde cross-linked forms of penicillin G acylase obtained from a mutant derivative of Escherichia coli ATCC 11105 were studied. Apparent activation energies for thermal inactivation of both native and cross-linked forms of enzyme were calculated to be [57.71 +/- 8.46] and [67.11 +/- 13.83] kcal mol-1 respectively. This slight increase in activation energy suggested that glutaraldehyde cross-linking did not markedly protect against thermal activation. Cross-linked enzyme did, however, have a significantly improved half-life at temperatures between 40 degrees C and 50 degrees C.
Cross-Linking Reagents↗
Toll-like receptor 2- and 6-mediated stimulation by macrophage-activating lipopeptide 2 induces lipopolysaccharide (LPS) cross tolerance in mice, which results in protection from tumor necrosis factor alpha but in only partial protection from lethal LPS doses.
Patients or experimental animals previously exposed to lipopolysaccharide (LPS) become tolerant to further LPS challenge. We investigated the potential of the macrophage-activating lipopeptide 2 (MALP-2) to induce in vivo cross tolerance to tumor necrosis factor alpha (TNF-alpha) and LPS. MALP-2-induced tolerance could be of practical interest, as MALP-2 proved much less pyrogenic in rabbits than LPS. Whereas LPS signals via Toll-like receptor 4 (TLR4), MALP-2 uses TLR2 and TLR6. LPS-mediated cytokine release was studied in mice pretreated with intraperitoneal injections of MALP-2. No biologically active TNF-alpha could be detected in the serum of MALP-2-treated animals when challenged with LPS 24 or 72 h later, whereas suppression of LPS-dependent interleukin (IL)-6 lasted for only 24 h. Protection from lethal TNF-alpha shock was studied in galactosamine-treated mice. Dose dependently, MALP-2 prevented death from lethal TNF-alpha doses in TLR4(-/-) but not in TLR2(-/-) mice, with protection lasting from 5 to 24 h. To assay protection from LPS, mice were pretreated with MALP-2 doses of up to 10 micro g. Five and 24 h later, the animals were simultaneously sensitized and challenged by intravenous coinjection of galactosamine and a lethal dose of 50 ng of LPS. There was only limited protection (four of seven mice survived) when mice were challenged 5 h after MALP-2 pretreatment, and no protection when mice were challenged at later times. The high effectiveness of MALP-2 in suppressing TNF-alpha, the known ways of biological inactivation, and low pyrogenicity make MALP-2 a potential candidate for clinical use.
Animals↗
Cross-achievements between policies for drinking water protection.
Environmental dynamics have important spatial dimensions, which calls for a spatial approach in policy analyses. Further to this, assessing agri-environmental policies involves analyses of individual measures as well as their combined effects on farmer behaviour and the environment. The integration of an economic behavioural model in a spatial framework has enabled analyses of a geographically targeted subsidy scheme for drinking water protection in combination with a uniform tax on commercial nitrogen fertilizer. Results show that policy measures for reducing nitrogen use can have combined effects (cross-achievements), thereby affecting each other's cost-effectiveness. Cross-achievements between a nitrogen fertilizer tax and a subsidy scheme based on elicitation are shown not to be additive, making partial analyses of policy measures more uncertain.
Agriculture↗
Antibodies to blood stage antigens of Plasmodium falciparum in rural Gambians and their relation to protection against infection.
Cross-sectional and longitudinal studies were performed in a rural population living in The Gambia to examine the relationship between several in vitro assays of the host immune response to asexual stages of Plasmodium falciparum and protection from malaria in vivo. Assays included an enzyme-linked immunosorbent assay for antibodies to schizont antigens; an indirect immunofluorescence assay for total antiblood-stage antibodies; an immunofluorescence assay on glutaraldehyde-fixed parasites to detect antibodies to antigen Pf 155; an assay for serum inhibition of red blood cell invasion; a micro-agglutination assay to detect antibodies to neo-antigens on the surface of infected red blood cells; and an assay using polymorphonuclear leucocytes to detect antibodies capable of opsonizing schizont infected red blood cells. There were marked differences in the age-related pattern of response for different assays performed on sera obtained at a cross-sectional survey of 280 individuals. Examination of the correlation between the various immune responses and malariometric indices at the population level and at the individual level provided no evidence that any of the in vitro assays were related to protective immunity. The relationship between in vitro measurements of the anti-malarial immune response and protection from clinical episodes of malaria was examined in a group of 134 children aged 11 years and under who were monitored weekly throughout an entire malaria transmission season. The only immune factor to show a consistent protective effect against clinical malaria was the titre of antibodies to neo-antigens on the infected erythrocyte surface (P = 0.01). The same longitudinal techniques were used to examine the effect of two non-immunological factors, sickle cell trait and mosquito net usage, both of which showed significant protection against clinical episodes and malaria.
Age Factors↗
Effects of vaccination with T cell receptor peptides: epitope switching to a possible disease-protective determinant of myelin basic protein that is cross-reactive with a TCR BV peptide.
Immunization of Lewis rats with guinea-pig myelin basic protein (Gp-MBP) induced T cell responses to primary and secondary encephalitogenic determinants, as well as to a third non-encephalitogenic epitope, residues 55-69. This sequence is of interest due to its protective activity against experimental autoimmune encephalomyelitis. Protection involved induction of MBP-55-69-specific T cells expressing cross-reactive TCR BV8S6 genes that activated regulatory T cells specific for TCR BV8S2 determinants expressed on encephalitogenic T cells. We here present and discuss new evidence suggesting a possible immunological cross-reactivity between the protective Gp-MBP-55-69 peptide and the regulatory BV8S2-39-59 peptide. This cross-reactivity, which may also occur between the human MBP-55-74 peptide and the BV12S2-38-58 sequence, has potentially important implications for human diseases such as multiple sclerosis.
Animals↗
Antigenic competition in a multivalent foot rot vaccine.
The antigenic competition that occurs when pilus antigens of different serogroups are combined in multivalent vaccines for foot rot has been investigated using recombinant pilus antigens. Our prototype vaccine contains pili from nine serogroups of Dichelobacter nodosus which are expressed in Pseudomonas aeruginosa. Sheep inoculated with this multivalent vaccine were not as well protected against foot rot as those given the monovalent vaccine. Levels of agglutinating and total antibody specific for any particular pili serogroup were found to be significantly reduced in sheep vaccinated with six or more closely related pili. This effect was more pronounced for agglutinating antibody, which is thought to mediate protection, but was also observed with total antibody levels measured by ELISA. The antigenic competition was not associated with the total antigen load as a tenfold higher dose of monovalent pili induced high titres of antibody. Furthermore, distributing the vaccine to four sites, each draining to a different lymph node, failed to overcome the competition. Experiments with mixtures of monospecific sera indicate that the phenomenon is unlikely to be due to blocking of serogroup-specific protective antibodies by an excess of cross-reactive non-protective antibody elicited by heterologous pili.
Agglutinins↗