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Results for “Cross Protection”

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PubMed2005

Synthesis and fluorescent properties of the tricyclic analogues of acyclovir linked with nitrogen hetbrocyclic units.

Tricyclic (T, 3,9-dihydro-9-oxo-SH-imidazo[g2-c]purine) analogues of acyclovir (ACV, 1), substituted in the 6 position with pyrid-4-yl, 4-(pyrid-4'-yl)Ph, 4-(pyrimidin-5-yl)Ph and 4-(thiazol-2'-yl)Ph units were synthesized. For the synthesis of the heteroarylphenyl derivatives, a convenient general route was developed, ie., Suzuki cross-coupling between protected 6-(4-dihydroxyborylphenyl) TACV and easily available bromoheterocycles. Fluorescent properties of newly synthesized TACV aoalogues strongly depend on the nature of a solvent. This sensitivity of fluorescence makes the compounds promising probes of H-bonding in the environment.

Absorption↗

PubMed1986

Heterologous protection against rotavirus-induced disease in gnotobiotic piglets.

Administration per os of 2 X 10(6) fluorescent cell-forming units of a human serotype 3 rotavirus (RV-3) protected all of nine gnotobiotic piglets against severe diarrheal disease when they were challenged 10 to 14 days later with 8 X 10(3) fluorescent cell-forming units of virulent wild-type porcine rotavirus (AT/76). The porcine virus was similar antigenically to porcine prototype strain OSU, previously described as antigenically distinct from all four recognized human serotypes. Administration of RV-3 was associated with the development of serum-neutralizing antibody to both RV-3 and AT/76 in piglets that excreted RV-3. Neutralizing antibody levels to RV-3 and AT/76 increased rapidly postchallenge. Vaccinated piglets were not immune to infection with AT/76 but showed no or minimal gastrointestinal symptoms after challenge. Control nonvaccinated piglets that were fed AT/76 developed severe dehydrating diarrhea and low levels of neutralizing antibody to AT/76 alone. The apparent heterologous clinical protection observed in this study could have been predicted from results of in vitro assays. Neutralization tests with reduction of fluorescence focus indicated a one-way cross-reaction between RV-3 and AT/76 such that hyperimmune antiserum to RV-3 neutralized porcine virus to moderate titer, but not vice versa. The results emphasize the importance of neutralizing antibody in protection against disease and the need to determine reciprocal cross-neutralization titers, rather than serotype alone, in order to predict the ability of rotavirus strains to cross protect.

Animals↗

PubMed2003

The molecular basis of the antigenic cross-reactivity between measles and cowpea mosaic viruses.

Two nonrelated viruses, cowpea mosaic virus (wtCPMV) and measles virus (MV), were found to induce cross-reactive antibodies. The nature of this cross-reactivity was studied and results are presented here demonstrating that antiserum raised against wtCPMV reacted with peptide from the fusion (F) protein of MV. Furthermore, the F protein of MV was shown to share an identical conformational B cell epitope with the small subunit of CPMV coat protein. Passive transfer of anti-wtCPMV antibodies into BALB/c mice conferred partial protection against measles virus induced encephalitis. The results are discussed in the context of cross-protection.

Amino Acid Sequence↗

PubMed1987

Does radiation exposure produce a protective effect among radiologists?

The mortality experience of radiologists compared to that of other physician specialists demonstrates an increased risk of cancer deaths as well as deaths from all causes among physicians practicing in the early years of this century. However, for the radiologists who joined specialty societies after 1940, the age pattern of deaths has changed. Whereas among early entrants, young radiologists had higher mortality rates than those of other specialists, among later entrants, the young radiologists have lower mortality. However, as these later-entrant radiologists age, their rates appear to exceed those of other specialists. Although the level of radiation exposure is unknown, physicians in more recent years usually have lower cumulative doses. Lower radiation exposure may be one of a number of possible explanatory factors for the cross-over from "protected" to "higher risk" status as these physicians age.

Adult↗

PubMed1991

[Orthotopic heart transplantation with sinus venosus incision of right atrium in dogs--preservation of sinus node and original right atrium].

Orthotopic heart transplantation with sinus venosus incision of right atrium was aimed to preserve the sinus node, terminal crista, sinus node artery and whole right atrial muscle of the transplanted heart. This transplant procedure was performed in eight mongrel dogs and electrocardiogram was followed up to five postoperative months. Direct cross circulation technique was employed as an alternative of cardiopulmonary bypass. Donors and recipients were 6 to 8 kg mongrel puppies, and 19 to 25 kg adult dogs supported the cross circulation. Myocardial protection of the donor heart was carried out by low-flow continuous potassium cardioplegia and topical cooling. Right atrial incision of the donor heart was made longitudinally in the posterior wall of sinus venosus. After a median sternotomy, ascending aorta and superior and inferior venae cavae of the recipient were cannulated and connected respectively with carotid artery and jugular vein of the cardiopulmonary support dog. Electrocardiogram, arterial pressure and central venous pressure of the recipient were monitored, and an electro-magnetic flow meter was employed for measuring the blood flow of direct cross circulation. The native heart was resected after aortic cross-clamping, and left atrium and atrial septum were sutured continuously. Sinus venosus incision of the donor heart was anastomosed to the recipient's right atrium. Ascending aorta and pulmonary trunk were reconstructed in the standard fashion. Aortic cross-clamp time was less than one hour and sinus rhythm of the transplanted heart was continued in all cases. Five of the eight dogs were alive postoperatively for one week to five months.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Comparative study of cerebral protection during surgery of thoracic aortic aneurysm.

During the past 5 years, 30 cases of thoracic aortic aneurysm were treated. Selective cerebral perfusion (SCP) and retrograde cerebral perfusion (RCP) were conducted for cerebral protection during aortic cross clamping. SCP was carried out in 5 cases of dissecting aneurysm (all Stanford type A, including a case of AAE) and 3 cases of arch aneurysm. RCP was conducted in 5 cases of dissecting aneurysm (4 Stanford type A, 1 Stanford type B with retrograde dissection) and 2 cases of aortic arch aneurysm. The mean cerebral perfusion time of SCP exceeded that of RCP (89 +/- 26 min in SCP versus 61 +/- 33 min in RCP p < 0.05). The hospital mortality rate was 38% (SCP) and 29% (RCP). Neurological complications were prolonged unconsciousness (1/8 in SCP, 1/7 in RCP) and transient paralysis (0/8 in SCP, 1/7 in RCP). Although the mechanism for the cerebral protective effect of RCP is unknown, this perfusion method is easy and safe, requiring little time for ascending and/or arch aortic reconstruction.

Aged↗

PubMedDate not supplied

Testing for loss of protective sensation in patients with foot ulceration: a cross-sectional study.

Current recommendations for the prevention of foot ulceration and amputation include screening at-risk individuals by testing for loss of protective sensation at eight sites using 10-g (5.07) nylon monofilaments. Yet measurement of the cutaneous pressure threshold to differentiate one-point from two-point static touch stimuli may allow identification of these at-risk individuals earlier in the clinical course of diabetic neuropathy. The present study tested this hypothesis using a prospective, cross-sectional, multicenter design that included sensibility testing of 496 patients with diabetic neuropathy, 17 of whom had a history of ulceration or amputation. Considering the cutaneous pressure threshold of the 5.07 Semmes-Weinstein nylon monofilament to be equivalent to the 95 g/mm(2) one-point static touch measured using the Pressure-Specified Sensory Device (Sensory Management Services LLC, Baltimore, Maryland), only 3 of these 17 patients with a history of foot ulceration or amputation would have been identified using the Semmes-Weinstein nylon monofilament screening technique. In contrast, using the Pressure-Specified Sensory Device, all 17 patients were identified as having abnormal sensibility, defined as greater than the 99% confidence limit for age, for two-point static touch on the hallux pulp. We conclude that patients at risk for foot ulceration can best be identified by actual measurement of the cutaneous sensibility of the hallux pulp.

Cross-Sectional Studies↗

PubMed1989

Infection control barrier techniques. Used by physicians during routine examinations. Parental attitudes.

Parents of 316 children seen in the outpatient clinics of a large pediatric teaching hospital completed a questionnaire regarding their attitudes toward the use of infection control procedures by doctors during the routine examination and treatment of their children. Results revealed that the majority of parents held favorable attitudes toward the wearing of gloves and masks during patient care activities. Parents who agreed that gloves and masks should be worn also tended to believe that diseases could be spread through cross-infection, that protective wear would prevent such infection, and that their children generally would benefit from these precautions. Parents of preschool-aged children felt that such procedures might make their children more fearful. These data indicate that many parents are basically supportive of the use of infection control procedures with their children and that such techniques do not appear to be an obstacle to effective relationships between health-care professionals and their patients.

Attitude↗

PubMed1998

Mechanism and specificity of immunoprotection induced by mycobacterial proteins against experimental tuberculosis in mice.

Mechanism of immunoprotection and specificity of two highly immunoprotective mycobacterial proteins, viz. 71 and 30 kDa were investigated. The adoptive transfer studies indicated that immunoprotection was mainly mediated by cooperative effect of CD4+ and CD8+ (66.7-73.3% on the basis of percent survival) which was further enhanced marginally by supplementation of B cells, natural killer cells, dendritic cells, macrophages and other immune cells. The specificity studies indicated that both the proteins did not cross react with the unrelated intracellular pathogens i.e. Aspergillus fumigatus, Salmonella typhi and Leishmania donovani as seen by T cell proliferation assay. The protection imparted by these mycobacterial proteins was also specific as the 71 and 30 kDa primed mice did not exhibit any cross protection against sublethal challenge of S typhi. The results indicate 71 and 30 kDa mycobacterial proteins to contain T cell specific epitopes responsible for specific immunoprotection, thus indicating their potential role as antituberculous vaccine candidates.

Animals↗

PubMed1997

Ca2+-independent permeabilization of the inner mitochondrial membrane by peroxynitrite is mediated by membrane protein thiol cross-linking and lipid peroxidation.

Peroxynitrite anion, the reaction product of superoxide and nitric oxide, is a potent biological oxidant, which inactivates mammalian heart mitochondrial NADH-coenzyme Q reductase (complex I), succinate dehydrogenase (complex II), and ATPase, without affecting cytochrome c oxidase (complex IV). In this paper, we evaluated the effect of peroxynitrite on mitochondrial membrane integrity and permeability under low calcium concentration. Phosphate buffer was used in most of our experiments since Hepes, Tris, mannitol, and sucrose were found to inhibit the oxidative chemistry of peroxynitrite. Peroxynitrite (0.1-1.0 mM) caused a dose-dependent decrease in the ability of mitochondria to build up a membrane potential when N,N,N',N'-tetramethyl-p-phenylenediamine/ascorbate were used as substrate. Elimination of the membrane potential was accompanied by penetration of the osmotic support (KCl/NaCl) into the matrix as judged by the parallel occurrence of mitochondrial swelling. This swelling was partially inhibited by dithiothreitol (DTT) or butylated hydroxytoluene (BHT) and was insensitive to ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, ADP, and cyclosporin A. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of solubilized membrane proteins indicated that alterations in membrane permeability were associated with the production of protein aggregates due to membrane protein thiol cross-linking. The protective effect of DTT on both mitochondrial swelling and protein polymerization suggests the involvement of disulfide bonds in the membrane permeabilization process. In addition, the increase in thiobarbituric acid-reactive substances and the partial inhibitory effect of BHT indicate the occurrence of lipid peroxidation. These results support the idea that under our experimental conditions peroxynitrite causes mitochondrial structural and functional alterations by Ca2+-independent mechanisms through lipid peroxidation and protein sulfhydryl oxidation.

Animals↗

PubMedDate not supplied

The influence of BCG vaccination on murine leprosy in C57BL/6 and C3H mice.

Cross-reactivity between Mycobacterium lepraemurium (MLM) and BCG vaccine was found and evaluated in vivo, in C57BL/6 mice, in terms of delayed-type hypersensitivity, local granulomatous response at the injected site and limitation of growth of the challenge inoculum in the draining node. Cross-reactive specific protection and local reactivities were transferred in syngeneic normal recipients by means of non-adherent lymphoid cells from immune donors. When BCG vaccine was injected either intravenously or subcutaneously in C57BL/6 and in C3H mice, it was able to induce resistance to local infection with living MLM in both strains, but no alteration of the local granulomatous reaction (equivalent to local specific immune response) was observed in C3H mice, as compared to the control. When mice were immunized with one or two injections of heat-killed MLM after the immunomodulating effect of BCG vaccination, better immunization was not achieved. In order to test the presence of strain-related immunosuppressive mechanisms, mice were cyclophosphamide-treated during the immunization process. As expected, higher specific DTH reactions were obtained in both strains, but with only a slight increase of the protective mechanism. Protection was always higher in C57BL/6 than in C3H mice. The specific and non-specific immune responses to BCG vaccine were then evaluated in both strains with different parameters: in vivo lymphoproliferative response in the draining node, delayed local granulomatous reaction at the injected site after a subcutaneous injection, increase in spleen index, kinetics of the immunopotentiation to a thymus-dependent antigen (sheep red blood cells) after a single intravenous injection of BCG. A striking interstrain difference was observed; C57BL/6 mice were able to mount a more rapid and marked immune response as compared to C3H mice (which only developed a delayed and slight response). Moreover, these differences were associated with the fact that BCG did not seem to multiply properly in C3H mice during the first two weeks after inoculation. Thus, it was concluded that higher natural resistance to pathogens and cross-reactive preimmunization with related microorganisms can interfere with the artificial immunization when living microorganisms are used. Implication for vaccination to mycobacterial infection (tuberculosis and leprosy) are discussed.

Animals↗

PubMed2003

Domestic cats infected with lion or puma lentivirus develop anti-feline immunodeficiency virus immune responses.

Attenuated live viral strains have afforded significant protection against virus challenge in HIV vaccine models. Although both cellular and humoral immunity are assumed to be vital for protection, specific parameters consistently associated with control of infection have been elusive. Our previous studies have shown that lentiviruses from 2 nondomestic feline species--lion (Pathera leo) and puma (Felis concolor)--persistently but nonpathogenetically infect domestic cats (Felis domestica). Moreover, infection with either the puma lentivirus (PLV) or lion lentivirus (LLV) conferred partial protection against superinfection with virulent feline immunodeficiency virus (FIV), the feline equivalent of HIV. To determine whether domestic cats infected by the lentiviruses of pumas or lions generate cross-reactive immune responses, we infected groups of 5 domestic cats with PLV, LLV, or a sham control and then monitored virus load, hematologic parameters, antibody protection, proliferative responses, and the ability of blood mononuclear cells to inhibit LLV, PLV, and FIV replication in vitro. All cats inoculated with LLV or PLV developed persistent infection, and low-level cell-associated viremia has been previously described. Infected cats also generated robust antibody titers and lymphocytes that proliferated in response to viral antigens and downregulated PLV, LLV, and FIV replication in vitro. This latter activity was CD8 cell associated for PLV and LLV inhibition but not for FIV inhibition. Thus, cats infected with the phylogenetically more ancient and less pathogenic feline lentiviruses generated humoral and cell-mediated immune responses reactive against both the homologous viruses and the heterologous FIV of domestic cats, which correlated with decreased viral load. These results are analogous to protection studies with attenuated primate immunodeficiency viruses and provide a system by which to examine adaptation, interference, and cross protection among lentiviruses.

Animals↗

PubMed2002

Diversity considerations in HIV-1 vaccine selection.

Globally, human immunodeficiency virus-type 1 (HIV-1) is extraordinarily variable, and this diversity poses a major obstacle to AIDS vaccine development. Currently, candidate vaccines are derived from isolates, with the hope that they will be sufficiently cross-reactive to protect against circulating viruses. This may be overly optimistic, however, given that HIV-1 envelope proteins can differ in more than 30% of their amino acids. To contend with the diversity, country-specific vaccines are being considered, but evolutionary relationships may be more useful than regional considerations. Consensus or ancestor sequences could be used in vaccine design to minimize the genetic differences between vaccine strains and contemporary isolates, effectively reducing the extent of diversity by half.

AIDS Vaccines↗

PubMed1998

[The use of hydrophobic PALL BB22-15MS filters in cross-infection prevention during anesthesia].

OBJECTIVE: Microbiological testing evaluations of hygienic procedure properties using PALL BB22-15MS filters to prevent contamination of "single use" breathing circuits during anesthesia. DESIGN: Prospective study. SETTING: Two operating rooms in a University hospital. PATIENTS: One hundred and thirty eight patients underwent general anesthesia for urologic surgery procedures. Patients with positive tests for HIV, B and C hepatitis and those considered to be at risk for HIV infection were excluded. The study was divided into five phases on the basis of times of usage of the same circuit for an increasing number of patients: in phase I, microbiological tests were performed on 4 circuits used on 4 different patients; in phase II the same tests were performed on 2 circuits each used on two different groups of three patients; in phase III, a circuit was used on a group of 15 patients and another on a group of 16 patients and the results were analysed; in phase IV a circuit used in a group of 32 patients was evaluated and phase V involved the analysis of a circuit that was used in a group of 65 patients. INTERVENTIONS: A filter was left in place between the patient and the circuit's Y-piece during all phases of anesthesia. The level of microbial contamination of breathing circuits was analysed in order to evaluate the reliability of the procedure. RESULTS: All analysed circuits remained uncontaminated. Staphylococcus hominis was revealed in respiratory circuit no. 6 of phase II, probably as a consequence of secondary contamination. CONCLUSIONS: Our results confirm that this procedure with the routine placement of a PALL BB22-15MS filter at the circuit's Y-piece can provide an adequate level of protection against cross-infections during anesthesia. The hygienic protocol proposed may allow the change of the anesthetic breathing only once a month.

Anesthesia, Closed-Circuit↗

PubMed1975

An attenuated variant of Eastern encephalitis virus: biological properties and protection induced in mice.

Wild type Eastern equine encephalitis virus (E) was compared with a mutant (Em) derived from it. The latter was tested as an attenuated vaccine in mice. They differed in the following properties: Em formed smaller plaques on chick embryo (CE) cell monolayers and, unlike E, did not plaque on mouse embryo (ME) monolayers. Futher, Em had a longer latent period and attained a lower peak titer than E after infection of CE cells, was more senssitive than E to chick interferon, and was less virulent for mice (SC and IP routes) and hamsters (IP route) than E. Both viruses were similar in several other properties tested. The mutant was found to induce a gradient in the specificity of protection in mice against challenge by selected viruses after a single subcutaneous injection of living virus. The protection was best against autologous (Em) challenge, was next best against challenge by the virulent parent (E) virus, but was not demonstrable against cross challenge by Venezuelan encephalitis (V) virus. Conventional hemagglutination-inhibiting (HI), complement-fixing (F), and neutralizing (N) antibodies could not be detected in Em-immunized mice even when fresh monkey or guinea pig serum was included in Ntests to provide complement and/or accessory factor(s). However, N antibodies were detected in protected mice by an indirect antiglobulin test. Passive protection by serum or ascites fluids (a.f.) was characterized by a lower but otherwise similar protection gradient like that found after active immunization with virus as described above. Interferon was not detected in the a.f. used for passive protection, nor was heterologous interference evident in Em immunized mice challenged 18 days later with vaccinia or vesicular stomatitis virus. Immunized mice that survived autologous (Em) challenge showed broadened protection against a second challenge by parent E virus, and cross protection against V virus. This typical protection was associated with the presence of HI and conventional N antibodies, except for V which showed no detectable neutralizing antibodies by either a standard or antiglobulin technique.

Animals↗

PubMed2006

o-nitrobenzyl photolabile protecting groups with red-shifted absorption: syntheses and uncaging cross-sections for one- and two-photon excitation.

We evaluated the o-nitrobenzyl platform for designing photolabile protecting groups with red-shifted absorption that could be photolyzed upon one- and two-photon excitation. Several synthetic pathways to build different conjugated o-nitrobenzyl backbones, as well as to vary the benzylic position, are reported. Relative to the reference 4,5-dimethoxy-2-nitrobenzyl group, several o-nitrobenzyl derivatives exhibit a large and red-shifted one-photon absorption within the near-UV range. Uncaging after one-photon excitation was studied by measuring UV-visible absorption and steady-state fluorescence emission on model caged ethers and esters. In the whole series investigated, the caged substrates were released cleanly upon photolysis. Quantum yields of uncaging after one-photon absorption lie within the 0.1-1 % range. We observed that these drop as the maximum wavelength absorption of the o-nitrobenzyl protecting group is increased. A new method based on fluorescence correlation spectroscopy (FCS) after two-photon excitation was used to measure the action uncaging cross section for two-photon excitation. The series of o-nitrobenzyl caged fluorescent coumarins investigated exhibit values within the 0.1-0.01 Goeppert-Mayer (GM) range. Such results are in line with the low quantum yields of uncaging associated with cross-sections of 1-50 GM for two-photon absorption. Although the cross-sections for one- and two-photon absorption of o-nitrobenzyl photolabile protecting groups can be readily improved, we emphasize the difficulty in enlarging the corresponding action uncaging cross-sections in view of the observed trend of their quantum yield of uncaging.

Journal Article↗

PubMed1990

Vaccination with inactivated influenza A virus during pregnancy protects neonatal mice against lethal challenge by influenza A viruses representing three subtypes.

A single intraperitoneal injection of pregnant mice with a monovalent Formalin-inactivated influenza A virus vaccine protected their offspring against a lethal challenge dose of the same influenza A virus H3N2, H2N2, and H1N1 subtypes, as well as against challenge with the other two subtypes. Degree of protection was vaccine dose related. Cross-fostering of neonates indicated that protection was conferred by breast milk antibodies. Serum virus-specific neutralizing antibodies in the mothers and neonates correlated with resistance to vaccine virus, but were detected against other subtypes only in a complement enhancement test or when high doses of vaccine were given.

Animals↗

PubMed2005

Cross-taxonomic potential and spatial transferability of an umbrella species index.

Validation that conservation of certain species effectively protects a high proportion of co-occurring species is rare. Our previous work has suggested that an umbrella index based on geographic distribution and life history characteristics would maximize the proportion of conspecifics protected per unit area conserved. Using bird and butterfly data from three mountain ranges in the Great Basin, we examined whether umbrella species also would confer protection to species in different taxonomic groups. Further, we addressed the spatial transferability of umbrella species by considering whether species identified as umbrellas in one mountain range would be effective umbrellas in other mountain ranges. Overall, equal proportions of species would be protected using either cross-taxonomic umbrella species or same-taxon umbrella species. Our data suggested that in a given mountain range, umbrella species identified using data from the same mountain range versus a different mountain range would be equally effective. The ability of one set of umbrella species to confer protection to co-occurring species, however, may vary among taxonomic groups and geographic regions.

Animals↗