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Biomedical subjects

S Nagy

Publications and source records attributed to S Nagy.

At least 19 recordsLinked to original sources

Optimal timing for intravenous administration set replacement.

BACKGROUND: Administration of intravenous therapy is a common occurrence within the hospital setting. Routine replacement of administration sets has been advocated to reduce intravenous infusion contamination. If decreasing the frequency of changing intravenous administration sets does not increase infection rates, a change in practice could result in considerable cost savings. OBJECTIVES: The objective of this review was to identify the optimal interval for the routine replacement of intravenous administration sets when infusate or parenteral nutrition (lipid and non-lipid) solutions are administered to people in hospital via central or peripheral venous catheters. SEARCH STRATEGY: We searched The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, CINAHL, EMBASE: all from inception to February 2004; reference lists of identified trials, and bibliographies of published reviews. We also contacted researchers in the field. We did not have a language restriction. SELECTION CRITERIA: We included all randomized or quasi-randomized controlled trials addressing the frequency of replacing intravenous administration sets when parenteral nutrition (lipid and non-lipid containing solutions) or infusions (excluding blood) were administered to people in hospital via a central or peripheral catheter. DATA COLLECTION AND ANALYSIS: Two authors assessed all potentially relevant studies. We resolved disagreements between the two authors by discussion with a third author. We collected data for the outcomes; infusate contamination; infusate-related bloodstream infection; catheter contamination; catheter-related bloodstream infection; all-cause bloodstream infection and all-cause mortality. MAIN RESULTS: We identified 23 references for review. We excluded eight of these studies; five because they did not fit the inclusion criteria and three because of inadequate data. We extracted data from the remaining 15 references (13 studies) with 4783 participants. We conclude that there is no evidence that changing intravenous administration sets more often than every 96 hours reduces the incidence of bloodstream infection. We do not know whether changing administration sets less often than every 96 hours affects the incidence of infection. In addition, we found that there were no differences between participants with central versus peripheral catheters; nor between participants who did and did not receive parenteral nutrition, or between children and adults. AUTHORS' CONCLUSIONS: It appears that administration sets that do not contain lipids, blood or blood products may be left in place for intervals of up to 96 hours without increasing the incidence of infection. There was no evidence to suggest that administration sets which contain lipids should not be changed every 24 hours as currently recommended.

Bacterial Infections↗

Head area measurements of dead, live, X- and Y-bearing bovine spermatozoa.

The head area of bull spermatozoa was measured after viability and acrosome staining using trypan blue and Giemsa stains, followed by X- and Y-chromosome-specific fluorescence in situ hybridisation (FISH). The former staining made possible the categorisation of cells according to morphology and membrane integrity, whereas the latter allowed distinction of spermatozoa bearing X- and Y-chromosomes. Individual spermatozoa could be followed during the consecutive steps of staining, measurement and FISH. Using a high-resolution digital imaging system and measurement software, the head area of more than 3000 cells of five bulls was determined precisely. In all bulls, morphologically normal, viable cells with intact acrosomes were significantly smaller than dead cells with damaged acrosomes. No significant difference in the head area between X- and Y-chromosome-bearing viable, acrosome-intact spermatozoa was found in individual bulls. However, significant between-bull differences were detected in all cell categories.

Acrosome↗

Effect of swim up and Percoll treatment on viability and acrosome integrity of frozen-thawed bull spermatozoa.

The aim of this study was to investigate the effect of the swim up and Percoll methods to select frozen-thawed bull spermatozoa with high quality membrane and acrosomal integrity and final concentration. Semen samples from six Holstein-Friesian bulls were examined. The whole experiment was repeated three times. Before and after both treatments, spermatozoa were subjected to a double-staining method and evaluated by brightfield light microscope using 40x dry, or 100x oil immersion objectives. The concentration of spermatozoa evaluated by haemocytometer was 8.8 x 10(7)/ml after thawing, and the percentage of live cells with intact acrosome was 45.8%. Both treatments significantly increased the proportion of live spermatozoa compared with no treatment, and the use of Percoll gradient resulted in a significantly higher percentage of living cells with an intact acrosome (88.2%) than the swim up method (69.4%). The concentration of spermatozoa after Percoll separation (9.3 x 10(6)/ml) was higher than that after the swim up method (5.8 x 10(6)/ml). These results indicate that spermatozoa with a higher viability and acrosome integrity can be obtained by Percoll separation than by the swim up method. Therefore the use of Percoll-treated spermatozoa in IVF systems can be more expedient.

Acrosome↗

Right-sided cervical aortic arch with stenosis--treatment with an extra-anatomic bypass graft.

Right-sided cervical aortic arch is a very rare vascular anomaly that may lead to stenosis development. Anatomic repair may be impeded by its high course or by abnormal branching of the supraaortic vessels, or both. This report will describe the treatment of a stenotic right-sided cervical aortic arch using an extra-anatomic bypass graft without extracorporeal support in an 11-year-old girl.

Aorta, Thoracic↗

[Biological aspects of the effectiveness/ineffectiveness of thrombocyte transfusions].

The clinical effect of platelet transfusions depends on a series of different factors and therefore it is not easy to explain the cause of inefficiency or that of the side-effects. Not only the immunhematological state of the patient, but the medical treatment and the properties of the platelet preparations should be taken into account. Platelet products prepared by standard techniques and stored according to the international recommendations possess different hemostatic effect. The effect of platelet storage conditions, aspects of platelet thermophysiology and current international tendencies regarding preparation and storage of platelet products are discussed. The choice of the proper platelet product has an essential impact on the clinical outcome.

Animals↗

Statewide Tuskegee Alliance for clinical trials. A community coalition to enhance minority participation in medical research.

BACKGROUND: Cancer mortality rates for all sites are nearly 2.5 times greater for African-Americans compared with whites. In addition, there are data implying that cancer treatment outcomes for minorities are unfavorable compared with whites. Whether this is due to poor access to health care or a biologic property of malignancies occurring in specific populations remains to be determined. Because of these unknown factors, targeting minorities for clinical trials may contribute toward the reduction of the overall morbidity and mortality associated with specific cancers. METHODS: The current study describes the establishment of a genuine collaborative partnership between the targeted minority community and clinical investigators at the University of Alabama at Birmingham. This partnership was formed for the purpose of identifying strategies that would enhance the accrual and retention of minority participants into current and future cancer prevention and control trials. Focus groups and key informant interviews were conducted to ascertain the community's perception of participating in clinical trials. RESULTS: The majority of focus group participants were unclear regarding the nature of clinical trials. Participants indicated that they would participate in research studies if they received adequate information regarding the purpose and benefits of the study, and if the charge came from a pastor or physician. Barriers to participation included time commitments, family obligations, whether blood was involved, and past experiences. The majority of the participants indicated that their knowledge of the Tuskegee Syphilis Study did not influence their decision to participate in research. A major outcome of the conference was the formation of the Statewide Tuskegee Alliance Coalition. The planning coalition decided to continue their efforts to work with communities and promote cancer awareness among minorities. After the conference, the coalition conducted several meetings and in July 1998, 1 year after the conference, the coalition selected a chair, co-chair, and a formal name for the organized group. CONCLUSIONS: The planning, development, and implementation of this conference provided a valuable experience for researchers and community members. It was discovered that community involvement in the early phase of this project contributed to its success. Furthermore, the partnership that developed between researchers (academic institutions) and communities successfully provided an infrastructure that supported the interest of both groups.

Adult↗

Nurses' beliefs about the conditions that hinder or support evidence-based nursing.

The aim of this study was to identify the conditions that Australian nurses believe support or hinder the development of evidence-based nursing. A survey instrument was developed from the results of content analysis of the UK and the USA research and of interviews with 12 Australian nurses. Eight hundred and sixteen nurses working in three large hospitals responded representing a response rate of 65%. Principal axis factor analysis of the survey results revealed six conditions that the participants believed were necessary for evidence-based nursing to take place. The results of this study may be used to develop models for the improvement of evidence-based nursing in Australia.

Adult↗

Evaluation of membrane integrity of frozen/thawed deer spermatozoa: short communication.

A simultaneous live/dead and acrosome staining, originally described for domestic mammals, was successfully applied on red deer (Cervus elaphus) and fallow deer (Dama dama) spermatozoa collected from the cauda epididymidis and vas deferens of shot stags. The staining is simple enough for routine application. Seven classes of spermatozoa were distinguished in the smears of frozen/thawed semen samples. Morphology, including cytoplasmic droplets, was evaluated as well. Percentage of live cells with intact acrosomes and with no other morphological aberrations might be a practical index of semen quality.

Acrosome↗

A sperm tail defect associated with infertility in a goat--case report.

Semen of an infertile Dutch White (Saanenthal) goat buck was examined. Light and electron microscopic examinations showed aberrations of the sperm tails resembling the so-called Dag or Dag-like defects described in several cattle breeds. Ejaculated semen showed that virtually all of the cells had strongly coiled or broken tails, or fractured midpieces. Ultrastructural investigations by transmission electron microscopy (TEM) showed uneven distribution of the mitochondria in the midpiece. Coiled tails were encapsulated by a common membrane, and dislocated axial fibres and different membranous structures were also present. The ultrastructural characteristics of the defective sperm tails, the missing parts of the axial fibre bundle and the misalignment of the mitochondria indicate that this first case reported in goat is similar to the Dag-like defect in cattle.

Animals↗

The influence of significant others on attitudes, subjective norms and intentions regarding dietary supplement use among adolescent athletes.

Dietary supplement use has increased significantly over the past decade. The use of supplements among adolescents seems to be influenced by their beliefs and attitudes. The influence of coaches, parents, and athletic trainers also may be important. The purpose of this study was (1) to determine whether attitudes are a better predictor of adolescents' intentions to use dietary supplements than are subjective norms, and (2) to assess the influence of significant others (coaches, parents, and trainers) on attitudes, subjective norms, and intentions among adolescent athletes. Adolescents (N = 1,626) who were enrolled in grades six through twelve in nine public schools completed a self-report questionnaire that measured attitudes, subjective norms, and intentions regarding dietary supplement use. Results indicated that attitudes were a better predictor of intentions to use dietary supplements than were subjective norms. It was also found that trainers had more influence on the attitudes, subjective norms, and intentions of adolescents regarding supplement use than did parents and coaches. Implications for prevention are addressed.

Adolescent↗

Endothelin-1 induces mucosal mast cell degranulation in the rat small intestine.

The enhanced production of endothelial cell-derived vasoactive mediators and the activation of mast cells (MCs) have been implicated in the pathogenesis of mucosal damage during ischemia and reperfusion injuries. The first objective of our study was to define the in vivo relation between endothelin-1 (ET-1) and the MC system. Secondly, we determined whether pretreatment with ET receptor antagonists would attenuate MC responses to exogenous ET-1. In the first series of experiments, increasing doses of ET-1 (0. 1, 1 and 3 nmol/kg i.v.) were administered to anesthetized rats. In the second series, the animals were pretreated with equimolar doses of the ET-A receptor antagonist BQ-610 or ETR-P1/fl peptide, and the ET-B receptor antagonist IRL-1038. Intestinal perfusion changes and macrohemodynamics were recorded, and the proportion of degranulated MCs was determined in ileal biopsies. The average mucosal thickness was recorded with an image analysis system. ET-1 induced dose-dependent alterations in the hemodynamic and morphological parameters and caused pronounced mucosal injury, with a significant reduction in villus height. The ratio of degranulated MCs was similar in all ET-treated groups (77%, 82% and 86%) to that observed in animals subjected to 15-min ischemia and 60-min reperfusion (85% degranulation). Pretreatment with BQ-610 and ETR-P1/fl peptide attenuated the ET-1 induced alterations in the hemodynamic parameters and decreased structural injury to the mucosa. ET-induced MC degranulation was significantly inhibited by the ET-A receptor antagonists, but not by IRL-1038. These results indicate that elevated levels of circulating ET-1 might induce intestinal mucosal tissue injury and MC degranulation via activation of ET-A receptors, and raise the possibility that ET-A receptor antagonist administration could exert a potentially beneficial effect through a mechanism other than the blockade of vasoconstriction in pathologies associated with an increased ET-1 release.

Amino Acid Sequence↗

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-induced changes in activities of nuclear protein kinases and phosphatases affecting DNA binding activity of c-Myc and AP-1 in the livers of guinea pigs.

To study the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on nuclear protein phosphorylation activities, male guinea pigs were treated in vivo with a single 1 microg/kg i.p. injection of TCDD, and the state of protein kinases and phosphatases in the nuclei of the hepatocytes was examined after 1, 10, and 40 days. TCDD was found to cause a rise in nuclear protein tyrosine kinase on day 1, and to a lesser extent on day 10, but this effect diminished almost completely on day 40. TCDD also caused a reduction in nuclear casein kinase II (CKII) activity at all time points. To study the biochemical events taking place at the early stage of the action of TCDD, a short-term in vitro model system was established using explant liver tissues maintained in tissue culture medium. It was found that TCDD caused a rapid reduction of the activity of nuclear CKII with an accompanying increase in the cytosol. Such changes in protein phosphorylation activities were also accompanied by an increase in the DNA binding activity of activator protein 1 (AP-1). The effect of TCDD on nuclear proteins binding to the c-Myc response element DNA was, on the other hand, biphasic: an initial increase of protein binding to the c-Myc response element was followed by suppression. To test the hypothesis that some of the above changes were caused by TCDD-induced changes in protein kinase activity, nuclear proteins isolated from hepatocytes of in vivo treated guinea pigs were incubated with exogenously added Mg2+ and ATP under cell-free conditions. The results showed that this in vitro phosphorylation treatment exacerbated this tendency of increased AP-1 and decreased c-Myc binding to their respective response element DNAs, indicating that kinases and phosphatases present in the isolated nuclear protein preparation were active and capable of modifying protein binding to DNA. Such effects of Mg2+ and ATP on AP-1 were blocked by heparin, indicating that CKII plays an important role in transducing the signal of TCDD into the nucleus.

Animals↗

Variability of standard clinical protein assays in the analysis of a model urine solution of fragmented albumin.

OBJECTIVES: This study investigates the sensitivity of various standard clinical techniques in the detection of albumin fragments. The significance of this work is in the detection of urinary proteins, such as albumin, which has recently been discovered to be excreted as mainly peptide fragments as a result of filtered albumin undergoing degradation during renal passage. All filtered proteins undergo a similar degradation process. DESIGN AND METHODS: Albumin digested with trypsin was used as a model urine solution. The solution was assayed for albumin concentration by various methods including the biuret assay that is known to detect urinary albumin fragments. The digest solution was also analyzed by various clinically used chromagen assays, electrophoretic and chromatographic methods to determine whether they are able to detect the fragmented protein. RESULTS: The benzethonium chloride, Coomassie blue, and pyrogallol red assays for urine protein, the immunoassay for human albumin and sodium dodecyl sulfate polyacrylamide gel electrophoresis with Coomassie blue staining were unable to detect the albumin fragments. Capillary electrophoresis was sensitive to the fragments but with low resolution. High-performance liquid chromatography gave the best results. CONCLUSIONS: Many techniques utilized to assay patient urine samples are unable to detect fragmented albumin and, hence, will severely underestimate albumin and protein excretion.

Albuminuria↗

Minority recruitment in clinical trials: a conference at Tuskegee, researchers and the community.

PURPOSE: This article describes the planning, implementation, and evaluation of a 2-day conference designed to examine the factors related to the participation of African Americans in cancer clinical trials. METHODS: Pre-conference formative evaluations (e.g., focus group discussions and key informant interviews with community leaders and health providers) were conducted in several rural and urban counties in the state of Alabama to determine African Americans' perceptions of participation in clinical research. The findings from these evaluations were used to develop a conference format and agenda. The 2-day conference included: (i) a pretest of African Americans' perceptions of cancer research, participation factors, and communication and recruitment issues; (ii) individual presentations high-lighting community leaders, church leaders, and researchers' perspectives regarding minority participation in research; (iii) working group discussions regarding the barriers and solutions to minority participation in research; and (iv) a posttest evaluation to measure changes in African Americans' perceptions of research. RESULTS: Several recruitment barriers and solutions were identified and reported by the working groups. Comparisons of the pretest and posttest measures showed significant (p > .05) and favorable shifts in the areas of perceptions of cancer research, participation factors, communication issues, and recruitment issues. Participation in the conference reflected a positive change in attitudes on these measures. However, the theme, "barriers that contributed to nonparticipation," did not show any significant changes during the two testing periods. The most critical lesson that resulted from this conference was the need for researchers and community members to have open dialogue about participation in research. CONCLUSIONS: This conference demonstrated that progress can be made when all parties are at the "table" and can be heard. In this model, community members proved to be valuable resources in providing researchers with information that was vital to the success of recruitment and retention studies and trials.

Black or African American↗

Prevention of early myocardial depression in hyperdynamic endotoxemia in dogs.

In our study the pathomechanism of sepsis-induced early myocardial depression was investigated. We determined the effects of the inducible nitric oxide synthase inhibitor and free radical scavenger mercaptoethylguanidine (MEG) on the myocardial contractility, the endothelial and inducible nitric oxide synthase (eNOS and iNOS) activities, and the activation and tissue accumulation of polymorphonuclear leukocytes in hyperdynamic endotoxemia in dogs. Group 1 served as endotoxemic control. Mean arterial pressure and cardiac output were measured, myocardial contractility was estimated from the end-systolic pressure-diameter relationship. The eNOS, iNOS and myeloperoxidase activities were determined on myocardial biopsy samples, and the free radical-producing capacity of granulocytes was measured from separated cells. The effect of MEG on the in vitro free radical production of isolated granulocytes was measured by chemiluminometry. Endotoxin induced a hyperdynamic circulatory reaction and significant myocardial depression. The myocardial eNOS activity was significantly increased 4 h after induction of endotoxemia and remained elevated, the iNOS activity was increased only 8 h after endotoxemia induction. The free radical-producing capacity and the myocardial accumulation of the granulocytes were significantly increased. In group 2, MEG treatment selectively inhibited the iNOS activity, prolonged the hyperdynamic circulatory reaction, prevented myocardial depression and decreased the activation and tissue accumulation of granulocytes. The compound dose-dependently decreased the in vitro activation of previously resting granulocytes. Our study demonstrates that iNOS do not contribute to the early cardiac failure in endotoxemia. MEG selectively inhibits iNOS in vivo, but its beneficial effects are rather related to the decreases in leukocyte and free radical-mediated myocardial dysfunction during early endotoxemia.

Animals↗