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Biomedical subjects

A Long

Publications and source records attributed to A Long.

At least 19 recordsLinked to original sources
PubMed2001

Simulation of acid-base condition and copper speciation in the fish gill microenvironment.

pH, alkalinity, and mucus content in the fish gill microenvironment of carp (Cyprinus carpio) were measured by exposing fish to copper at various water pH levels using an apparatus which separates inspired and expired water. The relationship between pH levels inside and outside of the gill microenvironment, between pH and alkalinity, and between mucus secretion, pH, and copper exposure concentration were modeled. Copper speciation in the surrounding water and in the fish gill microenvironment was simulated using MINTEQA2 chemical equilibrium calculation software. The results of the modeling for pH, alkalinity, and mucus calculation were then adopted as inputs for purposes of parameter identification in the speciation modeling. The differences observed in the copper species distribution between that of the fish gill microenvironment and the surrounding water were based on the speciation modeling. The change in copper bioavailability for fish uptake was also examined. The results indicate the presence of an experimental pH balance point at 6.9, where the pH in the fish gill microenvironment is identical to that of the surrounding water. The observed deviation range in pH levels between that found at the gills and that of the surrounding water varied from -0.4 to 0.8 units. A sinusoidal model was developed for calculation of gill pH based on the pH of the surrounding water. Models calculating alkalinity either in the gill microenvironment or in the surrounding water and for estimating mucus secretion were also developed. The results of the chemical equilibrium calculations demonstrate that, within a pH range of 6-9, the dominant species of copper in bulk solution shifted from free ions to that of the hydroxo complex. With respect to the fish gill microenvironment, the dominant species found under acidic conditions were the mucus copper complex and free ions. Because of the influence of mucus complexation and pH change, bioavailable copper species in the fish gill microenvironment were significantly lower than that in the bulk solution, especially under acidic conditions.

Acid-Base Equilibrium↗
PubMed2001

Crucial importance of PKC-beta(I) in LFA-1-mediated locomotion of activated T cells.

Crawling T cell locomotion in which activated lymphocyte function-associated antigen 1 (LFA-1) integrins participate is associated with translocation of the protein kinase C-beta (PKC-beta) isoenzyme to the microtubule cytoskeleton. In normal T cells and T lymphoma cell lines, this type of motility is accompanied by PKC-beta-sensitive cytoskeletal rearrangements and the formation of trailing cell extensions, which are supported by microtubules. Expression of PKC-beta(I) and enhanced green fluorescent protein (EGFP) in nonmotile PKC-beta-deficient T cells restored their locomotory behavior in response to a triggering stimulus delivered via LFA-1 and correlated directly with the degree of cell polarization. We have also shown that PKC-beta(I) is a component of the tubulin-enriched LFA-1-cytoskeletal complex assembled upon LFA-1 cross-linking. These observations may have physiological equivalents at advanced (post-integrin activation) stages of lymphocyte extravasation.

Cell Line↗
PubMed2001

The effectiveness of parenting programmes facilitated by health visitors.

AIM OF THE STUDY: This study was designed to evaluate the effectiveness of parenting programmes that are facilitated by health visitors and offer practical and emotional support to parents in the Down Lisburn Trust, Northern Ireland. METHODS: All parents (n=78) taking part were given a self-administered questionnaire both before and after attending a 'Positive Parenting' programme. The questionnaire contained items gathering demographic information, standardized measures of clinical anxiety/depression, personality states and coping styles and participants' experience of being a parent and what they wanted from the parenting group. Two items adapted from the Parent Stress Index looked at participants' ratings of themselves as parents, and if they enjoyed this role. STATISTICAL ANALYSIS: All statistics were computed using the SPSS for Windows (version 7) statistical package. The parametric paired-samples t-test was used with the ratio data generated by the Hospital Anxiety and Depression Scale (HADS) questionnaire. It is used to test the difference between the means of the pre and postsets of scores for significance. The nonparametric Wilcoxon test was used to find if there was a significant difference between the pre and postprogramme related samples by ranking the means. The Wilcoxon was chosen firstly because the data were ordinal in nature, hence it cannot be assumed that the findings follow the normal curve of distribution and secondly because it cannot be assumed that the data have homogeneity of variance. FINDINGS: At the end of the 8-week parenting programme, findings demonstrated significant statistically reduced levels of clinical anxiety and depression. Parents demonstrated an increase in more positive ratings of personality states such as not shouting at their children and being more calm and energetic at the end of the programme. Adaptive problem focused coping strategies were reported as being used more often subsequent to the programme, although some of the less adaptive emotion focused strategies had also increased in use. However, no change was evident in their ratings of how good a parent they were or if they enjoyed being a parent. CONCLUSIONS: Health visitors have the skills and are in the position to be preventative agents of inadequate parenting, and advocates of positive parenting. Factors relevant to the realm of positive parenting are highlighted as possible avenues for future research.

Adaptation, Psychological↗
PubMed2001

[Computer simulation of HA influence on copper bioavailability to the fish gills].

Copper speciation in the gill microenvironment of neon terris (Paracheirodon innesi) and the influence of humic acid and pH on copper bioavailability were investigated using exposure experiment and chemical equilibrium calculation. It was found that the copper speciation was changed because of the influence of the humic acid. With the existence of humic acid, the dominant species of copper in the bulk solution was humic acid complexed copper. However, humic acid complexed copper along with mucus complexed copper dominated the fish gill microenvironment. Consequently, the bioavailable copper species both in the bulk solution and in the fish gill microenvironment were significantly reduced by humic acid. The result of the modeling also indicated that the influence of pH was more significant under alkaline condition.

Animals↗
PubMed2000

Cross-linking of LFA-1 induces secretion of macrophage inflammatory protein (MIP)-lalpha and MIP-1beta with consequent directed migration of activated lymphocytes.

Cross-linking of LFA-1 induces an active locomotory phenotype in T cells. In this study we demonstrate that cross-linking of LFA-1 using a monoclonal antibody results in the secretion of MIP-1alpha and MIP-1beta. Similar results were seen with anti-CD44 but not with anti-transferrin receptor or anti-MHC class 1. We examined the ability of activated lymphocytes to migrate onto a substrate consisting of large protein G-Sepharose beads coated with anti-LFA-1 and anti-CD44. In this system a signal is provided by cells at the point of contact with the beads. Cells migrated to cover the bead surface within 24 h. This contact was shown to be inhibited by the introduction of neutralizing antibodies to MIP-1alpha and MIP-1beta. Hence cross-linking of LFA-1 or CD44 induce chemokine secretion which may be of relevance in directional migration of lymphocytes.

Antibodies, Monoclonal↗
PubMed2000

The influence of mucus on copper speciation in the gill microenvironment of carp (Cyprinus carpio).

pH and mucus (as total organic carbon) in the gill microenvironment of carp, Cyprinus carpio, exposed to various concentrations of total copper were measured in an exposure experiment using Playle's apparatus. The activities of free copper ions in both inspired and expired waters were determined using a copper ion selective electrode. A trial-and-error procedure of coupling species distribution calculations (MINEQA2) with single-site complexation modeling (mucus-copper) was proposed for computation of both copper speciation and complexation capacity of gill mucus for copper in an interactive loop. The method was demonstrated to be valid in calculating the metal speciation in this study. It was found that pH and alkalinity in the gill microenvironment were slightly higher than in the surrounding water of pH 6.7. The rates of excretion of CO(2), HCO(-)(3), and mucus at the gills increased, either linearly or nonlinearly with increases in the total copper concentration in the surrounding water. The conditional complexation stability constant of the mucus was calculated as log k=5.32, while the complexation stability equivalent concentration of the mucus was derived as 0.95 mmolCu/mgC. As a consequence of changes in pH and alkalinity, in conjunction with occurrence of mucus, copper speciation in the gill microenvironment is significantly different from that in the surrounding water, with 3-20% of the copper complexed by the gill mucus. The sequence of species domination also shifted from CuCO(0)(3), Cu(2+), CuHCO(+)(3), and Cu(OH)(0)(2) in the surrounding water to CuCO(0)(3), Cu(2+), Cu(OH)(0)(2), CuHCO(+)(3), and mucus-Cu in the gill microenvironment.

Animals↗
PubMed2000

Uptake of cadmium adsorbed on particulates by gills of goldfish (Carassius auratus).

Goldfish (Carassius auratus) were exposed to mixtures of constant dissolved cadmium (0.01 mg/L) and cadmium adsorbed on gibbsite particles at concentrations of 0, 0.025, 0.050, 0.075, and 0.100 mg/L. The gills of the fish were excised after a 5-day exposure experiment and both cadmium and aluminum in the gills were measured. The gills were also examined with a light microscope for surface adherence of the particles after the exposure. The evidence collected demonstrated that the concentration of cadmium in the gills increased with increased concentration of particulate cadmium during the exposure while the dissolved cadmium remained constant. The ratio of cadmium to aluminum in the gills was apparently higher than that in the solution, indicating the stripping and translocation of cadmium from the particles. A multistep uptake process is proposed and the bioavailability of particulate cadmium to fish gills is discussed.

Adsorption↗
PubMed2000

High multidrug resistance (P-glycoprotein 170) expression in inflammatory bowel disease patients who fail medical therapy.

BACKGROUND & AIMS: The multidrug resistance (MDR) gene codes for a drug efflux pump P-glycoprotein 170 (Pgp-170) expressed on the surface of lymphocytes and intestinal epithelial cells. Inflammatory bowel disease (IBD) poorly responsive to medical therapy may relate to MDR expression because glucocorticoids are known Pgp-170 substrates. METHODS: Using flow cytometry, we measured peripheral blood lymphocyte (PBL) MDR in 153 IBD patients and 50 healthy volunteers, and assessed the relationship between PBL, mucosal intraepithelial lymphocyte (IEL), and mucosal epithelial cell (EC) MDR expression in a further 20 IBD patients and 19 controls. RESULTS: Compared with controls, PBL MDR was significantly elevated in patients with Crohn's disease who required bowel resection for failed medical therapy (mean +/- SEM, 26.7 +/- 2.8 vs. 11.9 +/- 1.0; P <0.0001) and patients with ulcerative colitis who required proctocolectomy for failed medical therapy (20.3 +/- 2.5 vs. 11.9 +/- 1.0; P = 0.001). PBL MDR remained stable over time and was not influenced by disease activity or glucocorticoid therapy. Both PBL and mucosal MDR expression appeared independent of disease activity, and there was a significant correlation between PBL MDR expression and both IEL expression (r = 0.92; P < 0.0001) and EC expression (r = 0.54; P < 0.001). CONCLUSIONS: PBL and mucosal MDR expression may play an important role in determining the response of IBD patients to glucocorticoid therapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Role of vegetable tannins in habitat selection among mosquito communities from the Alpine hydrosystems.

The role of vegetable tannins in habitat selection among mosquito communities in Alpine hydrosystems was investigated through ecotoxicological comparison of 19 arthropod species characteristic of 12 breeding sites known for their abiotic environmental factors and their different riparian vegetation. The toxicity of tannins was experimentally compared among species representative of both the dipteran fauna and the crustacean fauna associated with the mosquito breeding sites. Bioassays using tannic acid solutions at concentrations from 0.1 to 11 mM separated the dipteran taxa into five groups of differential sensitivity and the crustacean taxa into four groups. The different levels of sensitivity among taxa were correlated with the various amounts of total phenolics and tannins found in the most prominent plant types associated with the different breeding sites. This suggested that tannins and, more generally, phenolic compounds may be involved in plant-arthropod interactions in Alpine hydrosystems.

Animal Feed↗
PubMed2000

The labyrinth of health as perceived by two groups of community nurses.

The purpose of this research was to examine a group of 16 health visitors and a group of 16 community mental health nurses perceptions of health and health awareness. The study was mainly qualitative and exploratory in nature with some quantitative data being collected to condense the data. All 32 respondents were interviewed using a semistructured, tape recorded format. The content of the data was scrutinized and emerging patterns, themes, and concepts were noted and coded using a tried and tested theoretical process. The findings were related to the questions asked and comparisons were drawn between the information received from each group. An examination of the data revealed that the group of health visitors defined health terms of 'functional' states, described health in physical terms, and practiced physical exercises as their health valuing behaviours in order to keep themselves healthy. This key theme also emerged with reference to their value of health at family and global levels. Taking their health for granted and being grateful for it when they saw someone in the community less well off than themselves was also highlighted as a major theme. The group of community mental health nurses defined their health in 'being' states and described health in a holistic manner. They perceived the value and concept of 'freedom' to be related to and embraced within the concept, definition and value of health at individual, family and global levels. They practiced aesthetic health valuing behaviours to enhance their appreciation of health and self. Mental health, the ability to make choices, being self actualizing and the capacity to love and be loved were the key themes emerging throughout this group's responses. It would be interesting to develop this research from a community health perspective.

Attitude of Health Personnel↗
PubMed2000

Colon signet ring cell adenocarcinoma: immunohistochemical characterization and comparison with gastric and typical colon adenocarcinomas.

Colon signet ring cell adenocarcinomas are uncommon, high-grade neoplasms. Given their rarity, the question of primary colon or metastatic gastric adenocarcinoma frequently arises when signet ring cell carcinoma is seen in a colonoscopic biopsy or in biopsies procured from other regions of the body. A second related question regarding colon and gastric signet ring cell carcinomas is their immunophenotypic similarities with the glandular form of adenocarcinoma in each site. We studied the immunohistochemical phenotype of 14 colonic signet ring cell adenocarcinomas and compared them with immunophenotype of 27 gastric signet ring cell adenocarcinomas. We also compared the immunophenotype of the 27 gastric signet ring cell with the immunophenotype of 19 gastric gland-forming adenocarcinomas, and the immunophenotype of the 14 colonic signet ring cell adenocarcinomas to the immunophenotype of 20 colonic gland-forming adenocarcinomas to identify staining differences in the neoplastic cells of the two architectures. Antibodies studied were cytokeratins 7, 17, 19, and 20, CA 19-9, CA-125. estrogen receptor, and gross cystic disease fluid protein 15. Sixty-four percent of colon signet ring cell adenocarcinomas had either no staining or focal staining with cytokeratin 7 compared with diffuse staining in 63% of gastric signet ring cell adenocarcinomas (P = 0.016). Seventy-two percent of colon signet ring cell adenocarcinomas had diffuse staining with cytokeratin 20 compared with no or focal staining in 50% of gastric signet ring cell adenocarcinomas (P = 0.019). Fifty-seven percent of the colon signet ring cell adenocarcinomas had a cytokeratin 7 (-)/cytokeratin 20 (+) staining pattern compared with 11% of gastric signet ring cell adenocarcinomas (P = 0.004). Forty-four percent of gastric signet ring cell adenocarcinomas had a cytokeratin 7 (+)/cytokeratin 20 (-) pattern, compared with none of the colon signet ring cell adenocarcinomas (P = 0.004). The staining distribution of the antibody battery was similar in colon signet ring cell and colon glandular adenocarcinoma and gastric signet ring cell and gastric glandular adenocarcinomas. When signet ring cell adenocarcinoma is encountered in a colon biopsy, a colon primary is supported if the neoplastic cells have a cytokeratin 7 (-)/cytokeratin 20 (+) staining pattern, and a gastric primary is supported if they have a cytokeratin 7 (+)/cytokeratin 20 (-) staining pattern. The signet ring morphology at each site had an identical immunophenotype as the cells forming their glandular counterpart.

Adenocarcinoma↗
PubMed2000

Hepatitis C lookback in Canada.

BACKGROUND AND OBJECTIVES: Since March 1990, all blood donations in Canada are screened by enzyme-linked immunosorbent assay (EIA) for antibodies to HCV, with confirmatory testing done using a recombinant immunoblot assay (RIBA). Because HCV may cause chronic asymptomatic hepatitis, in 1995, the Canadian Red Cross began targeted HCV lookback studies on all confirmed positive donations. These have been continued by the two new operators of the blood system in Canada, Héma-Québec and the Canadian Blood Services. Subsequent to recommendations made in the public inquiry into the Canadian blood system, led by judge Krever, general lookback through letter notification of all patients transfused in the years prior to the introduction of anti-HCV testing was initiated in several pediatric hospitals, and later in several Canadian provinces. MATERIALS AND METHODS: Targeted HCV lookback was done for all donors confirmed positive by RIBA testing from the start of HCV testing in 1990. In 1999, stored RIBA 2 indeterminate samples were re-tested by RIBA 3, and lookback performed on confirmed positive donations. In the province of Quebec, hospitals were surveyed to determine methods and resources involved in lookback. Provinces performing general letter notification entered hospital transfusion records into a central transfusion data bank, and performed linkage with other provincial data banks to remove deceased patients and obtain current addresses. RESULTS: As of January 2000, targeted lookback had been completed on 4,859 components of 1,628 anti-HCV positive repeat donors. 2,991 recipients were deceased, and 451 were not found or tested. Of the 1,422 recipients tested, 954 (67%) were anti-HCV positive. Approximately half were already aware of their HCV status. Lookback efforts in hospitals were hampered by lack of resources and manual records. General letter notification in British Columbia (BC) and Prince Edward Island (PEI) led to the testing of 38,960 and 1,953 recipients respectively, with 5.0 and 2.2% of tested recipients found to be anti-HCV positive. CONCLUSION: In completed targeted lookback investigations, 19% of components are eventually linked to an anti-HCV positive recipient. These results are very similar to those obtained in other countries, such as Denmark and the UK. In general letter notification lookbacks, the frequency of anti-HCV in the tested recipients is approximately twice the frequency of the general population.

Antibodies, Viral↗
PubMed2000

[Abdominal aortic aneurysm repair treated with endoprosthesis: technical and economic evaluation by ANAES(National Agency of Health Accreditation and Evaluation)].

OBJECTIVE: To evaluate the safety, efficacy and cost of stent-grafts for the endovascular repair of abdominal aortic aneurysms (AAA). MATERIALS AND METHODS: The ANAES report was based on a critical analysis of the published international literature and on consultation of technology assessment agencies. The report was reviewed by a group of experts and validated by the ANAES Scientific Council (Evaluation Section). RESULTS: The literature analysis indicated that the technique was feasible. However, it also revealed a shortage of methodologically sound clinical trials. The long-term outcome of the stent-grafts and the accompanying complications are not yet known. CONCLUSION: Further clinical studies are needed for a truly objective assessment. The ANAES working group has issued a series of recommendations designed to help physicians define the optimal conditions for the effective and safe use of these stent-grafts.

Aortic Aneurysm, Abdominal↗