PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Cross Protection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89Linked to original sources
PubMed1997

Lipid peroxidation, antioxidant status and troponin-T following cardiopulmonary bypass. A comparison between intermittent crossclamp with fibrillation and crystalloid cardioplegia.

OBJECTIVE: Intermittent crossclamp with fibrillation affords equivalent myocardial protection to cold crystalloid cardioplegia in patients undergoing elective coronary artery surgery. This study is a direct comparison between the two techniques with regards to free radical activity. METHODS: The study design was part of a prospective randomised trial. We studied 24 consecutive patients with ejection fraction of 30% or greater undergoing elective coronary artery surgery. Patients were randomised into two groups. In group 1 (n = 13) the myocardium was protected by intermittent aortic cross clamping with fibrillation and group 2 (n = 11) by antegrade cold crystalloid cardioplegia. The determinants of free radical activity were serial peripheral venous samples for lipid peroxidation and plasma antioxidant status (before and at 1, 6, 24 and 72 h after the end of cardiopulmonary bypass). The determinant of the efficacy of myocardial protection was serial peripheral venous samples of cardiac troponin-T taken at the same time intervals. RESULTS: The groups were similar with respect to age, sex distribution, preoperative ventricular function, left main stem disease, number of grafts and bypass times. Lipid peroxidation measurements at the 1 h time point were higher than preoperative values (7.24 +/- 1.19 vs. 4.48 +/- 0.69 and 9.36 +/- 1.46 vs. 4.98 +/- 1.02 (mean +/- S.E) in groups 1 and 2, respectively (units in mmol/l) thereafter values decreased to near preoperative values by 72 h. There was no significant difference between the groups (P = 0.42). Total plasma antioxidant status values at the 1 h time point were lower than the preoperative values for all patients (1.33 +/- 0.07 vs. 1.63 +/- 0.06 and 1.42 +/- 0.07 vs. 1.63 +/- 0.05 (mean +/- standard error) in groups 1 and 2, respectively, (units in mmol/l) and thereafter at the subsequent time points increased but never attained their preoperative value. There was no statistically significant difference between the two groups (P = 0.59). Troponin-T measurements showed no significant difference between the two groups at all time points (P = 0.2217). CONCLUSIONS: This study shows that lipid peroxidation is initially elevated and the defence mechanisms against oxygen free radicals-antioxidant status'-are depressed following cardiopulmonary bypass. The degree of oxygen free radical activity produced during ischaemia and reperfusion was similar in both types of myocardial protection employed in this study.

Adult↗
PubMedDate not supplied

Pyridoindole antioxidant stobadine protected bovine serum albumin against the hydroxyl radical mediated cross-linking in vitro.

On exposure to free radicals generated by the Fenton reaction system of Fe(2+)/EDTA/H(2)O(2)/ascorbate, bovine serum albumin (BSA), used as a model of water-soluble protein, was losing its water solubility depending on the concentration of the chelated iron. The precipitate was found irreversibly insoluble even in concentrated urea. In the soluble fraction, SDS-PAGE analysis proved the presence of dimers and trimers of BSA, accompanied by enhanced bityrosine fluorescence. The pyridoindole antioxidant stobadine inhibited the process of albumin insolubilization in a concentration-dependent manner, the protective effect being more efficient than that of 2-keto-4-methiolbutyric acid (KMBA). Stobadine was, however, less effective than trolox. The inhibitory effect of the antioxidants, expressed as IC(50), correlated well with the reciprocal values of corresponding second order rate constants for scavenging OHz.rad; radicals. The results indicated that the insolubilization of BSA induced by the Fenton system of Fe(2+)/EDTA/H(2)O(2)/ascorbate was caused by OHz.rad; radical mediated cross-linking of the albumin. The model system proved to be suitable for convenient testing of OHz.rad; radical scavenging ability of new antioxidants in a non-lipid environment.

Animals↗
PubMed1991

A case of a pseudomalfunction of a DDD pacemaker.

DDD pacemaker pseudomalfunction occurred in a 65-year-old man. This was due to premature ventricular contraction (PVC) response option and cross-talk detection window, which are designed to protect against pacemaker related tachycardia or cross-talk. Pseudomalfunction disappeared by eliminating PVC response option.

Aged↗
PubMed2004

Breast feeding, bottle feeding, and non-nutritive sucking; effects on occlusion in deciduous dentition.

AIMS: To assess the effect of the type of feeding and non-nutritive sucking activity on occlusion in deciduous dentition. METHODS: Retrospective study of 1130 preschool children (3-5 years of age) who had detailed infant feeding and non-nutritive sucking activity history collected by a structured questionnaire. They all had an oral examination by a dentist, blinded to different variables evaluated. RESULTS: Non-nutritive sucking activity has a substantial effect on altered occlusion, while the effect of bottle feeding is less marked. The type of feeding did not have an effect on open bite, which was associated (89% of children with open bite) with non-nutritive sucking. Posterior cross-bite was more frequent in bottle fed children and in those with non-nutritive sucking activity. The percentage of cross-bite was lower in breast fed children with non-nutritive sucking activity (5%) than in bottle fed children with non-nutritive sucking activity (13%). CONCLUSIONS: Data show that non-nutritive sucking activity rather than the type of feeding in the first months of life is the main risk factor for development of altered occlusion and open bite in deciduous dentition. Children with non-nutritive sucking activity and being bottle fed had more than double the risk of posterior cross-bite. Breast feeding seems to have a protective effect on development of posterior cross-bite in deciduous dentition.

Bottle Feeding↗
PubMed2006

Cross-reactivity of influenza A (H3N2) hemagglutination-inhibition antibodies induced by an inactivated influenza vaccine.

The antigenic drift of influenza A (H3N2) virus in 2003-2004 necessitated a change in the vaccine from the A/Panama to the A/Wyoming strain for the 2004-2005 season. Using hemagglutination inhibition, we therefore tested antibodies in sera of 39 individuals (mean age 64.6 years) at the end of the 2003-2004 season for cross-reactivity to vaccine strains and H3N2 antigens subject to antigenic drift. Antibodies against both A (H3N2) Panama and Wyoming developed in 5/13 (38.5%) unvaccinated individuals, whereas, 22/26 (84.6%) vaccinees developed antibodies to Panama and 21/26 (80.8%) to Wyoming. None of these individuals suffered an influenza episode that season. The results suggest that the elderly might develop protective levels of cross-reactive A (H3N2) Wyoming HI antibodies following vaccination with the Panama strain. Such strains, like the ones included in the 2003-2004 influenza vaccine, might be expected to provide a broad-spectrum antibody response that could be effective even in the face of single season antigenic drift.

Aged↗
PubMed2003

The human dopamine transporter forms a tetramer in the plasma membrane: cross-linking of a cysteine in the fourth transmembrane segment is sensitive to cocaine analogs.

Using cysteine cross-linking, we demonstrated previously that the dopamine transporter (DAT) is at least a homodimer, with the extracellular end of transmembrane segment (TM) 6 at a symmetrical dimer interface. We have now explored the possibility that DAT exists as a higher order oligomer in the plasma membrane. Cysteine cross-linking of wild type DAT resulted in bands on SDS-PAGE consistent with dimer, trimer, and tetramer, suggesting that DAT forms a tetramer in the plasma membrane. A cysteine-depleted DAT (CD-DAT) into which only Cys243 or Cys306 was reintroduced was cross-linked to dimer, suggesting that these endogenous cysteines in TM4 and TM6, respectively, were cross-linked at a symmetrical dimer interface. Reintroduction of both Cys243 and Cys306 into CD-DAT led to a pattern of cross-linking indistinguishable from that of wild type, with dimer, trimer, and tetramer bands. This indicated that the TM4 interface and the TM6 interface are distinct and further suggested that DAT may exist in the plasma membrane as a dimer of dimers, with two symmetrical homodimer interfaces. The cocaine analog MFZ 2-12 and other DAT inhibitors, including benztropine and mazindol, protected Cys243 against cross-linking. In contrast, two substrates of DAT, dopamine and tyramine, did not significantly impact cross-linking. We propose that the impairment of cross-linking produced by the inhibitors results from a conformational change at the TM4 interface, further demonstrating that these compounds are not neutral blockers but by themselves have effects on the structure of the transporter.

Cell Line↗
PubMed1999

Myocardial protection in operations requiring more than 2 h of aortic cross-clamping.

OBJECTIVE: Long periods of aortic cross-clamping time during cardiac surgery are associated with high rates of morbidity and mortality because of damage to the myocardium. Recently, we have used a method of myocardial protection based on the principles of hyperkalemic cardioplegic arrest. We use antegrade administration of warm, undiluted blood followed by continuous retrograde infusion of tepid, undiluted blood supplemented with potassium and magnesium. In this study, we have retrospectively reviewed our experience with this method of cardioprotection in operations requiring more than 2 h of cross-clamp time. METHODS: We retrospectively reviewed the medical records of 1280 patients who underwent myocardial revascularization, valve repair or replacement, or a combination of both operations between January 1, 1994 and December 31, 1997. Patients were divided into two groups: the short cross-clamp group (SXC) (n = 1144) had cross-clamp times < 120 min (mean, 78 +/- 20 min; range, 35-119 min) and the long cross-clamp group (LXC) (n = 136) had cross-clamp times > 120 min (mean, 154 +/- 31 min; range, 120-277 min). We compared preoperative, operative, and postoperative variables between the two groups. RESULTS: Significantly more patients in the long cross-clamp group (43.4%) underwent the combined operation than in the short cross-clamp group (2.3%), and the rate of reoperation was significantly higher in the long cross-clamp group (12%) than in the short cross-clamp group (5%). Despite these differences in operative complexity, we found no difference in hospital mortality rates between the two groups. The only significant postoperative differences were that the long cross-clamp group had a greater need for inotropic agents (43 vs. 29%), higher serum levels of creatine kinase (880 +/- 583 vs. 613 +/- 418) and CK-MB (10.9 +/- 6.4 vs. 5.9 +/- 5.2), and a longer hospital stay (9.6 vs. 6.1 days). CONCLUSION: Long, complex operations requiring more than 2 h of cross-clamping can be performed safely with our method of cardioprotection based on continuous retrograde infusion of tepid, hyperkalemic, undiluted blood.

Aged↗
PubMed1999

Protective effects of endothelin receptor antagonists in dogs with aortic cross-clamping.

Endothelin (ET) may play an important role in the pathogenesis of vasoconstriction and acute renal failure after aortic cross-clamping (ACC). However, the relative contribution of the ET(A) and ET(B) receptors to the physiopathology of ischemic acute renal failure is poorly understood. This study was carried out to evaluate the potential protective effect of a selective ET(A) antagonist versus combined ET(A)/ET(B) antagonist on altered systemic, pulmonary, and renal hemodynamics induced by cross-clamping the suprarenal aorta for 1 h, followed by 2-h reperfusion. Studies were performed in three groups of anesthetized mongrel dogs. After baseline measurements, treatment (3 mg/kg i.v. bolus + 3 mg/kg/h infusion) with either a selective ET(A) antagonist, Ro 61-1790 (n = 5), or a combined ET(A)/ET(B) antagonist, bosentan (n = 5) or vehicle (n = 8) was initiated 5 min before ACC. There were marked increases in total peripheral (TPR), pulmonary (PVR), and renal (RVR) vascular resistances, and significant decreases in cardiac output (CO) and glomerular filtration rate (GFR) and tubular sodium reabsorption after ACC in the vehicle group. Both Ro 61-1790 and bosentan prevented the marked increases in TPR, PRV, and RVR, and attenuated the declines in CO, GFR, and tubular sodium reabsorption. We concluded that the profound systemic, pulmonary, and renal vasoconstriction, as well as the impairments in glomerular and tubular functions associated with ACC, is mostly ET mediated and that the ET(A) receptor activation makes a major contribution to the ET-mediated impairments of hemodynamics and renal function after ACC.

Acute Kidney Injury↗
PubMed2005

Clustering of protective factors for glucose intolerance and insulin resistance: a cross-sectional study.

AIMS: A cluster of interrelated factors: a body mass index (BMI) < 25 kg/m(2), moderate exercise and alcohol intake, non-smoking and a favourable dietary pattern has been linked with markedly reduced risk of Type 2 diabetes. The aim of this study was to estimate the prevalence of a similar low-risk group in a sample of middle-aged Irish men and women, and determine whether this cluster is associated with a reduced risk of glucose intolerance (IFG and Type 2 diabetes according to ADA/WHO criteria) and insulin resistance [homeostasis model assessment (HOMA) score in upper quartile of distribution]. METHODS: A cross-sectional study involving a stratified random sample of 1018 general practice patients, aged 50-69 years. We defined a low-risk group based on the following variables: BMI < 25 kg/m(2); waist-hip ratio < 0.85 for women and 0.90 for men; never smoking status; participation in medium to high level of physical activity; light drinking (3.5-7 units of alcohol per week) and a 'prudent' dietary pattern. Valid data were available for glucose tolerance status and HOMA score and all exposure variables from 684 and 671 participants, respectively. RESULTS: A total of 7.5% of participants had none of the 'protective factors', 24.9% had one, 31.0% two, 23.3% three, 10.0% four, 3.0% five and 0.3% had six protective factors. In multivariate analyses the odds ratios for insulin resistance were 0.59, 0.48, 0.14 and 0.04 in persons with one, two, three and four or more low-risk factors, respectively, relative to those with none. Similar linear inverse trends were observed for glucose intolerance. CONCLUSIONS: The findings are consistent with an inverse linear relation between a cluster of core protective, lifestyle-related factors and the prevalence of both glucose intolerance and insulin resistance.

Aged↗
PubMed1999

Child protection: a survey of experience and knowledge within the dental profession of New South Wales, Australia.

AIM: To establish the experience and knowledge of dental practitioners in New South Wales, Australia in the area of child abuse and protection. DESIGN: A cross-sectional telephone questionnaire. SAMPLE: One hundred and twenty-two interviews; 67 general dental practitioners randomly selected and 55 members of the Australia and New Zealand Society of Paediatric Dentistry. RESULTS: All of the dentists interviewed could identify physical abuse and most identified emotional abuse, however, none could describe all five forms of abuse. Significantly more (58%) members of the paediatric dental society had at some time suspected abuse, compared with only 24% of the general practitioners. However, only 20 of the paediatric dentists and seven general practitioners had actually reported any cases. The main reason given for not reporting concerned confidentiality. Seventy-two per cent of general practitioners did not know their legal obligations or with whom they could discuss any concerns. While paediatric dentists achieved a better percentage, still over half of them were similarly unsure. CONCLUSIONS: Further education and training is required for both the dental profession and the child protection agencies to improve the inter-agency working relationship and thus provide better protection for children.

Attitude of Health Personnel↗
PubMed2005

Immunodominant viral peptides as determinants of cross-reactivity in the immune system--Can we develop wide spectrum viral vaccines?

When we look back to Edward Jenner vaccination of a young man in 1796, we cannot help thinking that he was both lucky and crazy. Crazy because he decided to test in a human being a hypothesis based mainly in the traditional belief that people who had acquired cowpox from the udders of a cow were thereafter resistant to smallpox, a quite devastating disease, and lucky because (even considering that he did not know this at that time) he succeeded to induce protection against a pathogen through the induction of an immune response directed against a different agent. Not only was he able to protect the young man but he took the first step towards the development of a vast new field, vaccination. It is acceptable to say that Jenner was lucky because he succeeded in promoting protection against smallpox using a cowpox virus and this induction of protection in a cross-reactive way is believed to be quite rare. Nevertheless, more and more examples of cross-reactive immune responses are being described and we are beginning to admit that cross-reactivity is far more common and important than we used to think. Here we review cross-reactivity in the immune system and the plasticity of T cell recognition. Based on the existence of T cell receptor promiscuous recognition and cross-recognition of conserved viral immunodominant epitopes, we propose two approaches to develop wide spectrum viral vaccines. The first one is based on the identification, characterization, and cloning of immunodominant viral epitopes able to stimulate responses against different viruses. The produced peptides could then be purified and serve as a basis for vaccine therapies. A second strategy is based on the identification of conserved patterns in immunodominant viral peptides and the production of synthetic peptides containing the amino acid residues necessary for MHC anchoring and TCR contact. Although we are still far from a complete knowledge of the cross-reactivity phenomenon in the immune system, the analysis of immunodominant viral epitopes and the identification of particular "viral patterns" seems to be important steps towards the development of wide spectrum viral vaccines.

Animals↗
PubMed1982

Enhanced protection of myocardial function by systemic deep hypothermia during cardioplegic arrest in multiple coronary bypass grafting.

The effectiveness of deep systemic hypothermia (20 degrees C) in myocardial protection during aortic cross-clamping was elevated. Seventy-one consecutive patients undergoing coronary artery bypass grafting were divided into two groups. In group A (32 patients) systemic temperature was reduced to an average of 26.8 degrees C (range 24 degrees to 28 degrees C) and the amount of cardioplegic solution infused totalled 1,000 to 1,200 cc. In Group B (39 patients) systemic temperature was reduced to an average of 20.8 degrees C (17 degrees to 23 degrees C) and the total amount of cardioplegic solution infused was 100 to 300 cc. The mean number of coronary (distal) anastomoses per patient was 4.46 in Group A and 4.51 in Group B. There were no surgical deaths, perioperative infarcts, or neurologic damage in either group. Postoperative catecholamine dependence was used as an indicator for inadequate myocardial protection. Catecholamine support was required by 18 patients (56.25%) in Group A and two patients (5.13%) in Group B (p less than 0.0001). Patients of both groups who received five or six coronary anastomoses, whose aortic cross-clamp time was 60 minutes or more, and whose preoperative left ventricular ejection fractions were above 50% were compared: Ten of the 11 (91%) in Group A required catecholamine support as opposed to none of the 12 in Group B (p less than 0.0001). No significant difference in the incidence of catecholamine requirement was found between patients of both groups whose aortic cross-clamp time was less than 60 minutes (2/13 patients in Group A and 2/21 patients in Group B), regardless of their preoperative left ventricular ejection fraction. We conclude that when aortic cross-clamp time exceeds 60 minutes, that is, when multiple distal anastomoses are performed, deep systemic hypothermia is a simple and effective method for myocardial preservation.

Adult↗
PubMed1989

Active immunization against virus infections due to antigenic drift by induction of crossreactive cytotoxic T lymphocytes.

We have examined whether active immunization with c13 protein, a hybrid protein of the first 81 amino acids of the viral NS1 nonstructural protein and the HA2 subunit of A/PR/8 (H1N1) hemagglutinin, could protect BALB/c mice from challenge with A/PR/8 H1 subtype virus. Mice immunized with the c13 protein had a significant reduction of pulmonary virus titers with A/PR/8 (H1) virus, but failed to limit the replication of A/PC (H3) virus, which reflects the in vitro CTL activity of c13 immune spleen cells. We observed that the epitope recognized by HA2 specific CTL, which are induced by a derivative of c13 protein, is highly conserved among H1 and H2 subtype virus strains. This led us to test whether active immunization with c13 protein would also limit pulmonary virus replication in mice infected with the A/TW virus, a virus of the H1 subtype, which was isolated in 1986, and with a virus of the H2 subtype, A/Japan/305/57. Immunized mice had significantly lower lung virus titers than did control mice, and did not possess any neutralizing antibodies to the challenger viruses. These results indicate that active immunization with a fusion protein containing the cross-reactive CTL epitope protects mice from influenza infection by inducing CTL against influenza A H1 and H2 subtype virus strains, which markedly vary in their antibody binding sites on the HA1. The ability to induce active cross-reactive immunization with a fusion protein which contains a highly conserved CTL epitope offers a model for vaccine approaches against viruses which undergo significant variations in their antibody binding sites.

Animals↗
PubMed2003

Social capital as a predictor of adolescents' sexual risk behavior: a state-level exploratory study.

This exploratory study assessed the state-level association between social capital, poverty, and income inequality and adolescents' sexual risk and protective behaviors. A cross-sectional design using state-level correlations was employed. Seven outcome measures from the national 1999 Youth Risk Behavior Surveillance Survey were used. For females and males, social capital was significantly associated with five of the seven outcome measures (all associations p < 01). For females, the amount of variance explained by these correlations ranged from 23% to 45%; the range for males was 20% to 52%. Poverty was not a significant predictor of any outcome variable. Income inequality was a significant predictor of birth control usage among females, but in multivariate regression analyses, only social capital retained significance. Findings provide preliminary evidence that social capital may have a profound influence of adolescents' sexual risk and protective behaviors. Social capital was inversely correlated with sexual risk behaviors and positively correlated with protective sexual behaviors. Further and more comprehensive research involving social capital and adolescents is warranted.

Adolescent↗
PubMed1981

Partial purification and characterization of protection-inducing antigens from the muscle larva of Trichinella spiralis by molecular sizing chromatography and preparative flatbed isoelectric focusing.

The soluble portion of a large particle fraction which was derived from the muscle larva of T. spiralis was subjected to molecular sizing column chromatography using Sephacryl S-200. Five major peaks of 280 nm absorbing material were obtained. Analysis by immunoelectrophoresis revealed that each peak contained antigens, with the majority of them occurring in peaks 3, 4 and 5. Preliminary studies indicated that peak 4(mol. wt range 20 000--10 000) contained protection-inducing antigens. Crossed-immunoelectrophoretic and single-dimension electrophoretic analysis of peak 4 revealed a minimum of 10 antigens, while analytical isoelectric focusing demonstrated the presence of proteins with widely different pl, ranging from 4.0 to 9.0. Peak 4 was fractionated by preparative flatbed isoelectric focusing (PIEF) using two gradients: one from 3.5 to 9.5 and the other from 3.5 to 5.5. Fused rocket immunoelectrophoretic (FRIEP) analysis of both runs indicated that several antigens were separated from the others: one at pl 4.0 and the other at pl 9.0. The remaining antigens focused between pl 4.3 and 4.9. One hundred micrograms of whole peak 4, pl 9.0 antigen and the group of antigens at pl 4.3--4.9 were each separately injected, along with Freund's complete adjuvant, into mice. In addition, a portion of the pl 4.0 antigen was also assayed for protection. All antigenic preparations induced significant levels of protection. The pl 4.0 was further analysed on high-performance liquid chromatography (HPLC). Two sharp peaks of antigen, as detected by FRIEP, were eluted isocratically with 65% acetonitrile from a C-18 (aliphatic) column. Both peaks of antigen showed complete cross-reactivity on FRIEP and absorbed at 220 nm. Amino acid analysis of each HPLC peak revealed no detectable differences in composition. Each peak contained predominance of aspartic (13 mol%) and glutamic (18 mol%) acid. This antigen did not contain significant quantities of aromatic amino acids, and absorbed strongly at 206 nm. Neither the pl 4.0 or pl 9.0 antigen stained positively with the PAS reaction.

Amino Acids↗
PubMed2000

Entonox equipment as a potential source of cross-infection.

A survey of the hospitals with obstetric units within the Anglia and Oxford Region was performed to assess current practices regarding the cleaning of, and use of filters with, Entonox apparatus. The survey revealed that there was no consensus regarding the cleaning of the equipment and, in contrast to anaesthetic machines in which microbiological filters are recommended and in widespread use, only 10% of the hospitals surveyed were using such filters with the Entonox apparatus in their units. Cleaning procedures were changed in 75% of hospitals when dealing with known 'high-risk' patients, the remaining hospitals treating all patients as 'high-risk' or denied caring for such patients. All patients should be protected from potential cross-infection, and the recommendation that a microbiological filter should be placed between patients and the breathing system should be extended to Entonox equipment.

Cross Infection↗