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PubMed2002

Peroxidase-catalyzed oxidative coupling of phenols in the presence of geosorbents: rates of non-extractable product formation.

Oxidative coupling processes in subsurface systems comprise a form of natural contaminant attenuation in which hydroxylated aromatic compounds (HACs) are incorporated into soil/sediment organic matter matrices. Here we describe the oxidative coupling of phenol catalyzed by horseradish peroxidase (HRP) in systems containing two geosorbents having organic matter of different composition; specifically Chelsea soil, a near-surface geologically young soil having a predominantly humic-type soil/sediment organic matter (SOM) matrix, and Lachine shale, a diagenetically older natural material having a predominantly kerogen-type SOM matrix. It was found that each of these two different types of natural geosorbents increased the formation of non-extractable coupling products (NEPs) over that which occurred in solids-free systems. The extent of coupling was higher in the systems containing humic-type Chelsea SOM than in those containing kerogen-type Lachine SOM. It was observed that HRP inactivation by free radical attack was significantly reduced in the presence of each geosorbent. A rate model was developed to facilitate quantitative evaluation and mechanistic interpretation of such coupling processes. Experimental rate measurements revealed thatthe greater extent of reaction observed in the presence of Chelsea soil than in the presence of Lachine shale can be attributed to two factors: (i) more effective protection of HRP from inactivation by the Chelsea SOM and (ii) the greater reactivity of Chelsea SOM with respect to cross-coupling. Interrelationships among enzyme protection, cross-coupling reactivity, and SOM chemistry are discussed.

Adsorption↗

PubMed1995

Induction of protective immunity to schistosomiasis with immunologically cross-reactive Lumbricus molecules.

Immunologically cross-reactive molecules of Schistosoma japonicum and Lumbricus terrestris were identified by antibodies derived from human and rodent sera. Pooled IgG from schistosomiasis patients but not uninfected individuals bound multiple antigens of identical molecular weight in both soluble S. japonicum worm antigen preparations (SWAP) and soluble earthworm preparations (SEWP). These antigens had molecular weights corresponding to 18, 40, 62, 64, 74, 97, and > 110 kDa. Three of these antigens of 74, 97 and > 110 kDa were immuno-affinity purified using antibodies derived from schistosomiasis patients' sera. Vaccination of mice with SEWP produced murine antibodies which bound parasite molecules of 40, 74, 97, and > 110 kDa and induced 36% protection from S. japonicum infection (P < 0.05). Antibody production to S. japonicum paramyosin, a molecule previously shown to induce protection from schistosome infection, was prominently expressed in the protected murine immune sera. The study shows that Lumbricus sp. represent a potential source for paramyosin and other candidate vaccine molecules for schistosomiasis.

Animals↗

PubMed1986

Burn therapy 1985: acute management.

Mortality occurs from a burn injury because of infections which result from the metabolic and bacterial consequences of a large open wound, depression of the host's resistance, and both protein and total caloric malnutrition. Systemic antibiotics, topical wound therapy, and gentle wound debridement constitute traditional burn therapy. The systemic antibiotics and topical wound therapy do not solve problems presented by large open wounds and the related protein and caloric deprivation. A more rational approach uses antibiotics and topical wound therapy only as adjuncts to a program of early operative removal or excision of the devitalized, burned tissue and immediate closure of the wound. The excised wound is normally closed with available autograft, but in massive burn injuries, donor skin is insufficient. In these massive injuries, artificial skin can provide that immediate wound closure. As long as devitalized, burned tissue remains present in the setting of depressed host resistance, cross infection tends to colonize those remaining devitalized burn wounds with more virulent organisms than those that were already present. Bacterial controlled nursing units (BCNU) provide strict protection against that cross infection. Though inevitably a catabolic response occurs with massive injury, intensive nutritional support provides the calories necessary for the response to injury to avoid a prolongation of that negative nitrogen balance.

Administration, Topical↗

PubMed1996

Protection by coffee against somatic genotoxicity in Drosophila: role of bioactivation capacity.

The protective effects of coffee against somatic mutation and mitotic recombination induced by cyclophosphamide (CPH), mitomycin C (MMC) and urethane (URE) were evaluated in the standard (ST) and high bioactivation (HB) crosses of the wing spot test in Drosophila melanogaster. These two crosses are characterized by different constitutive levels of cytochrome )-450-dependent enzyme activities. 3-day old larvae transheterozygous for the wing cell markers mwh (multiple wing hairs) and flr3 (flare3) were fed until pupation on medium containing a genotoxin alone or its combination with different concentrations of instant coffee. subsequently, the wings of the resulting adult flies were analysed for detecting single spots (mwh or flr3) originating from mutational or recombinational events as well as twin spots (mwh and flr3) originating exclusively from recombination. The results showed high sensitivity of the HB cross to URE. Co-administration of instant coffee was effective in exerting significant dose-related inhibitory effects on the genotoxicity of URE in the ST and the genetically susceptible HB cross. Similarly, coffee showed significant dose-related inhibitory effects on the genotoxicity of MMC in both crosses. The same protective effect was also observed with one concentration of coffee in combination with CPH. Pretreatment of 2-day-old HB larvae with coffee for 24 hr followed by treatment with URE was also effective in significantly reducing the induction of mutation and recombination. The magnitude of the protective effects of coffee against these three genotoxins was independent of the genotype of the larvae used for treatment, that is it was independent of the bioactivation capacity of these larvae. The study demonstrates the suitability of this assay for obtaining qualitative and quantitative data on the result of interactions among a genotoxin, an inhibitor of genotoxicity and bioactivation capacity of the host.

Animals↗

PubMed1993

Big brother.

Both purchasers and providers will need to change the way they hold patient records on computer, or they could find themselves in breach of the law. Michael Cross examines a report by the Data Protection Registrar.

Computer Security↗

PubMed1991

The role of barrier precautions in infection control.

Barrier precautions are a fundamental component of any infection control strategy and a critical aspect of all isolation systems. Because many infections are transmitted from patient-to-patient via the hands of personnel, gloves and gowns are widely recommended to provide an extra measure of protection against cross-infection. It is not clear whether gloves are superior to handwashing (if performed obsessionally) in this respect, and there is little evidence that gowns confer additional benefit. These concerns notwithstanding, barrier precautions can substantially reduce the risk of some infections, such as respiratory syncytial virus disease. On the other hand, the modes of transmission of many infections are complex (e.g. with rotavirus) or controversial (e.g. with rhinovirus), and, even though hands are involved in transmission, barrier precautions alone may not suffice to prevent spread. Moreover, neither gloves nor gowns can prevent nosocomial infections caused by endogenous microbial flora; perhaps this explains the limited efficacy of barrier precautions in reducing the endemic rate of infection due to bacteria such as Pseudomonas aeruginosa in intensive care units. Barrier precautions may also fail if colonized patients are not identified promptly. One potential solution to this problem is 'body substance isolation' (BSI), in which all patients are considered to be potential carriers of nosocomial pathogens whether or not they have been cultured or have developed a clinical infection. In BSI barrier techniques are used when any potentially contaminated patient material is handled. BSI also provides barrier protection from bloodborne pathogens for personnel.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗

PubMed1998

Dual effect of actin on the accessibility of myosin essential light chain A1 to papain cleavage.

The influence of various amounts of actin on the proteolytic susceptibility of myosin essential light chain (ELC) A1, the binding of isolated A1 light chain and the N-peptide spanning N-terminal sequence of A1 to actin is studied to obtain more information on the role of the N-terminus of A1 light chain in the myosin-actin interaction. Low ratios of actin to myosin (1:1) lead to stimulate cleavage, whereas higher ratios (4:1) lead to protection of A1. Exposure of A1 by actin is especially seen in heavy meromyosin (HMM) and monomeric myosin and this is probably related to the full saturation of actin protomers with myosin heads. The protecting action of actin on A1 cleavage is more pronounced in myosin filaments. Conditions favoring the saturation of myosin regulatory light chain (RLC) with calcium ions instead of magnesium ions promotes the protection of A1. Cross-linking of HMM and actin results in higher yields of A1-actin product at high actin to myosin heads ratios. Isolated A1 light chain is pelleted by actin. A synthetic peptide spanning the N-terminal sequence of A1 can be cross-linked to actin. It is postulated that the protective action of actin on A1 papain cleavage is caused by the binding of the A1 N-terminus to actin. Changes in the RLC phosphorylation level and magnesium-for-calcium exchange in RLC may affect the probability of this interaction.

Actins↗

PubMed1978

Broadly reacting precipitating and agglutinating antigen of leptospirae.

A saprophytic Leptospira biflexa strain of equine origin was found which cross-reacts with immune rabbit antisera to 14 pathogenic Leptospira interrogans serotypes. Sera from goats experimentally inoculated with the saprophyte showed multiple low-level cross-agglutination reactions against a battery of live L. interrogans serotypes. Sonically treated and saline-extracted suspensions of the L. biflexa strain and serotypes canicola, icterohaemorrhagiae, and pomona yielded a common precipitating protein antigen that was detected by immunodiffusion and immunoelectrophoresis with all of the antileptospiral sera examined. In cross-absorption and gel diffusion tests, the precipitinogen from each of the strains was shown to be identical. Formaldehyde treatments and heating at 100 degree C suggest that the cellular location of the common antigen is either somatic or subsurface, and Sephadex G-200 gel filtration enabled the isolation of the active fraction of the L. biflexa antigen. Monoprecipitin sera against the common antigen of L. biflexa were produced by immunizing rabbits with specific precipitates in agar. In gel diffusion and immunoelectrophoresis tests the antisera with each of the soluble antigens developed a single precipitin formation, and the antisera agglutinated formolized and heated whole-cell suspensions of serotypes canicola, icterohaemorrhagiae, and pomona at low dilutions. The soluble L. biflexa antigen was evaluated as an immunogen and in passive immunity tests for protection against death and kidney infection in hamsters. No cross-protection occurred when the hamsters were challenged with virulent leptospires. In contrast, the animals vaccinated or administered hamster immune serum before challenge died earlier than the control animals.

Animals↗

PubMed1992

Sun exposure in Australian adolescents.

BACKGROUND: Little information is available on the sun-related behavior of teenagers despite the considerable resources spent to decrease sun exposure in this age group. OBJECTIVE: Our purpose was to describe the sun exposure behavior of Australian adolescents and define characteristics that predict use of sun protection. METHODS: Cross-sectional study of a random sample of 972 school students 13 to 15 years of age from three different locations in Australia (two urban and one rural) using a diary to document sun exposure and sun protection on two consecutive weekends. RESULTS: More than 80% of adolescent boys in each place and more than 60% of adolescent girls in both of the large cities spent more than 2 hours outdoors during the peak ultraviolet (UV) periods on each weekend. Neither sunscreen nor hats were used for more than half the time spent in the sun; however, shirts were worn most of the time. Students who wore hats were more likely to be boys (odds ratios [OR] = 2.2, 95% confidence intervals [CI] 1.40 to 3.44) and live in the rural region (OR = 4.6, 95% CI 2.36 to 9.04). Students who used sunscreen tended to have skin that sunburned easily (OR = 3.2, 95% CI 1.27 to 7.88) and score highly on the knowledge questions (OR = 2.9, 95% CI 1.46-5.69). This model was not a good predictor of behavior on a subsequent weekend, possibly because behavior was highly variable, with 35% to 50% of students changing their pattern of protection use from one weekend to the next. CONCLUSION: Adolescents spend long periods on summer weekends in the sun and do not follow recommended sun protection guidelines. The high variability of sun-related behavior makes modeling and consequent development of education programs a difficult task.

Adolescent↗

PubMed1979

[Myocardial protection from cardioplegic and hypothermia during aortic cross-clamping (author's ttrans)].

The clinical results with cardioplegic solutions and hypothermia during aortic cross-clamping are compared with the clinical results obtained with hypothermia only. To complete the study miocardial biopsies were obtained during aortic cross-clamping in order to evaluate the concentration of ATP and CPK. The obtained data confirm the effectiveness of the myocardial protection.

Adenosine Triphosphate↗

PubMed1998

The biological relevance of virus neutralisation sites for virulence and vaccine protection in the guinea pig model of foot-and-mouth disease.

Five neutralisation epitopes have been defined for the O1 Kaufbeuren strain of foot-and-mouth disease virus (FMDV) by neutralising murine monoclonal antibodies (Mabs). A mutant virus which is resistant to all these Mabs also resists neutralisation by bovine polyclonal sera, and this characteristic was exploited in the current study to investigate the biological relevance of neutralisation sites in FMDV virulence and vaccine protection. The five site neutralisation-resistant mutant was shown to be as pathogenic as wild-type virus in the guinea pig model of FMD. Guinea pigs were protected in cross-challenge studies from virulent wild-type and mutant viruses using either wild-type or mutant 146S antigen as inactivated whole virus vaccine. Furthermore, hyperimmune sera raised to either wild-type or mutant antigen offered passive protection against wild-type challenge, in spite of the serum raised against the mutant antigen having minimal neutralising activity in vitro. These results imply that virus neutralisation, at least as defined by the in vitro assay, may not play an essential role in the mechanism of immunity induced by whole inactivated FMDV vaccines.

Animals↗

PubMed1996

Discrete transcripts encode multiple chitinase isoforms in Brugian microfilariae.

The blood-borne microfilariae of the Brugian nematodes produce multiple isoforms of chitinase, whose expression is coincident with the onset of microfilarial infectivity for mosquitoes. A single cDNA sequence was previously obtained by screening a Brugia malayi microfilarial cDNA library, yet two chitinase isozymes are readily distinguished in this species. In this paper, we present evidence for the existence of multiple transcripts encoding Brugian microfilarial chitinases. Using primers based on the previously-sequenced cDNA clone, we amplified and sequenced two discrete products from B. malayi microfilarial RNA by RT-PCR. While the shorter fragment was nearly identical to the previously sequenced cDNA, the larger fragment contained an extra copy of a serine/threonine-rich repeat. RNAse protection assays were used to demonstrate that both sequences represent true transcripts, and not PCR artifacts. Using primers based on the B.malayi sequence, two novel sequences were generated by RT-PCR from B. pahangi microfilariae. Homologous and cross-species RNAse protection assays verified that multiple transcripts also encode chitinase isozymes in B. pahangi microfilariae.

Amino Acid Sequence↗

PubMed1995

Intelligence and temperament as protective factors for mental health. A cross-sectional and prospective epidemiological study.

The Sjöbring system of personality dimensions measuring intellectual capacity, activity, impulsivity and sociability was used to study possible "salutogenic" (i.e. causes of health) effects. The study comprised 590 subjects investigated in 1947, 1957, 1972 and 1988-1989 in the Lundby project, an epidemiological study in Sweden. Psychiatric diagnoses were made in 1947, 1957 and 1972. Mental health was estimated in 1988-1989 using the concept "love well, work well, play well and expect well". The Sjöbring dimensions were clinically assessed in 1972. Both in the concurrent study in 1972 and in the prospective study in 1988-1989 "super capacity" (high intellectual function), "super validity" (high activity level) and "super solidity" (low impulsivity) were statistically associated with lower frequencies of certain psychiatric diagnoses and a higher frequency of positive mental health. These variables are proposed to increase coping capacity, and therefore increase stress resilience.

Adolescent↗

PubMed1986

"Crossing balloons:" a new technique for complex angioplasty.

A new technique is described for complex percutaneous transluminal coronary angioplasty of a lesion at the bifurcation of the obtuse marginal branch of the left coronary artery, just distal to a venous bypass graft insertion. Two separate angioplasty guide wire and catheter systems were used and the coronary artery side branch was protected in a "crossing" manner.

Adult↗

PubMed2000

Erythropoietin crosses the blood-brain barrier to protect against experimental brain injury.

Erythropoietin (EPO), recognized for its central role in erythropoiesis, also mediates neuroprotection when the recombinant form (r-Hu-EPO) is directly injected into ischemic rodent brain. We observed abundant expression of the EPO receptor at brain capillaries, which could provide a route for circulating EPO to enter the brain. In confirmation of this hypothesis, systemic administration of r-Hu-EPO before or up to 6 h after focal brain ischemia reduced injury by approximately 50-75%. R-Hu-EPO also ameliorates the extent of concussive brain injury, the immune damage in experimental autoimmune encephalomyelitis, and the toxicity of kainate. Given r-Hu-EPO's excellent safety profile, clinical trials evaluating systemically administered r-Hu-EPO as a general neuroprotective treatment are warranted.

Animals↗

PubMed2000

Inducible protective processes in animal systems VI. Cross-adaptation and the influence of caffeine on the adaptive response in bone marrow cells of mouse.

The effect of caffeine (CAF) (a replicative DNA synthesis inhibitor) given as pre-, inter- and post-treatments on the ethyl methanesulfonate (EMS)-induced adaptive response in in vivo mouse bone marrow cells was studied in order to understand the influence of CAF on the adaptive response. The pre-treatment was given 4 h before a combined treatment with EMS (conditioning + challenge) and in another set CAF was given as a conditioning dose and 4 h later the cells were challenged with a high dose of EMS. In the inter-treatment, CAF (40 mg/kg body wt) was administered 2 or 4 h after the conditioning dose of EMS and 6 or 4 h later the cells were challenged with a high dose of EMS. Similarly, in the post-treatment experiments, CAF was injected 6, 12 or 18 h after a combined treatment with EMS. The results revealed that the pre-, inter- and post-treatments with CAF significantly reduced the frequency of chromosomal aberrations compared with the challenge and combined treatments with EMS. It is interesting to note that CAF pre-treatment resulted in a much greater reduction in chromosomal aberrations compared with the inter- and post-treatments. Thus, this is an example of cross-adaptation induced by CAF in EMS-treated in vivo mouse bone marrow cells and the results also demonstrate an influence of CAF on the adaptive response.

Acclimatization↗

PubMed2000

Iloprost protects the spinal cord during aortic cross-clamping in a canine model.

BACKGROUND: Surgical procedures on the thoracoabdominal part of the aorta make the spinal cord vulnerable to ischemia. Paraplegia is the most severe complication following thoracoabdominal operations. In this study, iloprost was used as an agent to decrease the severity of ischemia and reperfusion injury to the spinal cord during aortic occlusion and declamping. METHODS: Twelve adult mongrel dogs weighing 17+/-2 kg were used in this study. The animals were randomly assigned to either group I, which received saline solution (6 dogs), or group II, which received prostacyclin. Group I was referred to as the control group and group II as the iloprost group. After baseline measurements were completed, the aorta was cross-clamped for sixty minutes distal to the left subclavian artery. No pharmacologic agents were used to control blood pressure in group I. Proximal and distal mean arterial pressures (DMAP) were monitored continuously. DMAP were considered as diastolic pressure in preocclusion and reperfusion periods. Iloprost administration was started at a rate of 5 ng/kg/minute five minutes before the aortic occlusion. This dosage was increased to 25 ng/kg/minute during aortic occlusion. RESULTS: Mean proximal arterial pressure was 147+/-12 mmHg in the control group and 116+/-13 mmHg in the iloprost group at occlusion (p<0.01). Mean distal arterial pressure was 19+/-7 in the control group and 37+/-5 in the iloprost group during clamping (p<0.05). Functional outcome was evaluated according to Tarlov scores 24 hours after the study. Although none of the animals recovered completely from the control group, 4 animals from the iloprost group recovered (p<0.05). Following the neurologic assessment, animals were sacrificed and specimens were taken for the electron microscopic study. Electron microscopic changes documented that severe mitochondrial damage and vacuolisation occurred in the control group. However these changes were more subtle in the iloprost group. CONCLUSIONS: As a result of this study we concluded that iloprost infused before and during clamping of the thoracic aorta mitigates the spinal cord injury due to ischemia and reperfusion following unclamping.

Animals↗

PubMed1988

In vitro protection of the articular surface by cross-linking agents.

The effects of cross-linking agents on the resistance of the articular surface to digestion with clostridial collagenase were studied using a described in vitro system. Mouse femoral heads were treated with various concentrations of glutaraldehyde, with osmium tetraoxide and with dithiobis (succinimydil propionate), digested with the enzyme, labeled with cationized ferritin and examined by electron microscopy. Collagenase alone caused disruption of the articular surface with penetration of the large marker into the cartilage matrix. After treatment of the femoral heads with the cross-linking agents, no effects on the morphology and on the labeling of the articular surface and no penetration of the label into the cartilage matrix were observed. Increasing cross-linking at the articular surface might be a new route for therapeutic intervention. However, experiments would be needed to assess the effect of the procedure on the viability and nutrition of chondrocytes and on the functional properties of the tissue.

Animals↗