Treadmill exercise during adenosine infusion is safe, results in fewer adverse reactions, and improves myocardial perfusion image quality

BACKGROUND

Combining low-level treadmill exercise with adenosine infusion may result in fewer bradyarrhythmic complications by increasing sympathetic tone and may improve myocardial perfusion image quality by decreasing background activity.

METHODS

Patients referred for outpatient pharmacologic stress myocardial perfusion imaging performed simultaneous treadmill exercise (mean 2.2 metabolic equivalents) throughout 6-minute adenosine infusion (adenosine-exercise n = 507). Patients unable to exercise and those with left bundle branch block received adenosine infusion alone (adenosine-nonexercise n = 286). Adverse reaction data were collected on all patients and compared by sex. Background-to-target activity was calculated in a blinded fashion on 200 randomly selected patients.

RESULTS

During the period from April 1996 to December 1998, 507 patients (64%) underwent adenosine-exercise testing, whereas 286 (36%) underwent adenosine-nonexercise testing. Hypotensive and arrhythmic (atrioventricular block, sinus bradycardia, and new onset atrial fibrillation or flutter) adverse reactions occurred less often during adenosine-exercise than during adenosine-nonexercise. Neither death nor myocardial infarction occurred in either group. In the adenosine-exercise group, 2.8% of patients experienced an adverse reaction versus 5.6% of the adenosine-nonexercise group (P = .04). The reduction in adverse reactions occurred in both men and women, although women had significantly more adverse reactions than men (5.7% vs 1.8%, P = .004). Liver/heart and gut/heart ratios were lower in the adenosine-exercise group (1.05+/-0.42 vs. 1.21+/-0.55 , P = .01; 0.61+/-0.21 vs. 0.69+/-0.24, P = .03, respectively).

CONCLUSIONS

Compared with adenosine infusion alone, combining low-level treadmill exercise with adenosine in outpatients is safe, better tolerated, and improves image quality. Women were more likely to experience adverse reactions than men.

Calcium signaling induced by adhesion mediates protein tyrosine phosphorylation and is independent of pHi

Our goal was to evaluate early signaling events that occur as epithelial cells make initial contact with a substrate and to correlate them with phosphorylation. The corneal epithelium was chosen to study signaling events that occur with adhesion because it represents a simple system in which the tissue adheres to a basal lamina, is avascular, and is bathed by a tear film in which changes in the local environment are hypothesized to alter signaling. To perform these experiments we developed a novel adhesion assay to capture the changes in intracellular Ca(2+) and pH that occur as a cell makes its initial contact with a substrate. The first transient cytosolic Ca(2+) peak was detected only as the cell made contact with the substrate and was demonstrated using fluorimetric assays combined with live cell imaging. We demonstrated that this transient Ca(2+) peak always preceded a cytoplasmic alkalization. When the intracellular environment was modified, the initial response was altered. Pretreatment with 1,2-bis(o-aminophenoxy)ethane-N,N, N'N'-tetraacetic acid (BAPTA), an intracellular chelator, inhibited Ca(2+) mobilization, whereas benzamil altered the duration of the oscillations. Thapsigargin caused an initial Ca(2+) release followed by a long attenuated response. An inositol triphosphate analog induced a large initial response, whereas heparin inhibited Ca(2+) oscillations. Inhibitors of tyrosine phosphorylation did not alter the initial mobilization of cytosolic Ca(2) but clearance of cytosolic Ca(2+) was inhibited. Exposing corneal epithelial cells to BAPTA, benzamil, or thapsigargin also attenuated the phosphorylation of the focal adhesion protein paxillin. However, although heparin inhibited Ca(2+) oscillations, it did not alter phosphorylation of paxillin. These studies demonstrate that the initial contact that a cell makes with a substrate modulates the intracellular environment, and that changes in Ca(2+) mobilization can alter later signaling events such as the phosphorylation of specific adhesion proteins. These findings may have implications for wound repair and development.

Negative correlates of computer game play in adolescents

There is some concern that playing computer games may be associated with social isolation, lowered self-esteem, and aggression among adolescents. Measures of these variables were included in a questionnaire completed by 204 year eight students at a North London comprehensive school. Principal components analysis of a scale to assess needs fulfilled by game play provided some support for the notion of 'electronic friendship' among boys, but there was no evidence that game play leads to social isolation. Play was not linked to self-esteem in girls, but a negative relationship was obtained between self-esteem and frequency of play in boys. However, self-esteem was not associated with total exposure to game play. Aggression scores were not related to the number of games with aggressive content named among three favourite games, but they were positively correlated with total exposure to game play. A multiple regression analysis revealed that sex and total game play exposure each accounted for a significant but small amount of the variance in aggression scores. The positive correlation between playing computer games and aggression provides some justification for further investigation of the causal hypothesis, and possible methodologies are discussed.

A randomized prospective study of radially expanding trocars in laparoscopic surgery

Trocar injury is one of the most serious and potentially preventable complications of laparoscopic surgery. Use of a blunt rather than a cutting trocar could be expected to lessen the likelihood of this injury. Therefore complications related to laparoscopic port design were studied by comparing conventional cutting trocars with radially expanding (blunt) trocars. A multicenter, prospective, randomized clinical trial was conducted in 250 adult patients undergoing elective laparoscopic procedures at tertiary care centers and community hospitals. The patients were randomly assigned to one of two groups: group C, conventional cutting trocars; or group S, radially expanding trocars. Sixteen surgeons performed 244 elective laparoscopic procedures; six patients were removed from the study. One hundred nineteen patients were assigned to group S and 125 to group C. The groups were similar with regard to age, sex, and type of procedure. The following data were collected: intraoperative complications related to the trocars, abdominal wall bleeding, visceral or vascular injury, other complications, fascial closure, procedure time, trocar site assessment at 4 and 24 hours postoperatively, and visual analog pain scores at 4, 8, 12, and 24 hours postoperatively. Fascial defects from 10 mm or larger trocars in group C were closed; the fascial defects in group S were not closed. The trocar sites were checked for incisional hernias at late follow-up. Mean operating time was not different between the two groups (group S, 92 +/- 73 minutes; group C, 100 +/- 74 minutes). There were no episodes of intraoperative cannula site bleeding in group S compared with 16 episodes in 13 patients (P < 0.001) in group C. Postoperative wound complications were fewer in group S (13 vs. 23; P < 0.05). Although the pain scores were generally lower in group S, the differences were not significant. Only 3% of the patients in group S had fascial defects of 10 mm or greater that had to be closed. Within a follow-up period of 6 to 18 months, there have been no incisional hernias in either group. This study shows that radially expanding trocars are safe and effective, and less likely than conventional trocars to result in intraoperative or postoperative complications. The defects created by the radially expanding trocars do not have to be routinely closed.

Do eicosanoids cause colonic dysfunction in experimental E coli O157:H7 (EHEC) infection?

BACKGROUND

The pathophysiology of enterohaemorrhagic Escherichia coli (EHEC) infection remains unclear. Eicosanoids have been implicated as pathophysiological mediators in other colitides.

AIMS

To determine if prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) contribute to mucosal inflammation and dysfunction in EHEC colitis.

METHODS

Ten day old rabbits were infected with EHEC. For five days after infection, mucosal synthesis of PGE(2) and LTB(4) was measured in distal colonic tissue from control and infected animals and (51)Cr-EDTA permeability was assessed in vivo. Myeloperoxidase activity was measured and histological inflammation and damage were assessed at five days in control and infected animals and after treatment of infected animals with the LTB(4) synthesis inhibitor MK-886. In separate experiments, ion transport was measured in Ussing chambers, before and after in vitro addition of the cyclooxygenase inhibitor indomethacin.

RESULTS

LTB(4) synthesis was increased from day 2 after infection onwards and PGE(2) synthesis was increased on day 3. Mucosal permeability did not increase until day 5 after infection. MK-886 inhibited colonic LTB(4) production but did not reduce diarrhoea, inflammation, or mucosal damage. Electrolyte transport was not significantly altered on day 3 after infection. However, both Cl secretion and reduced Na absorption found on day 5 were partially reversed by indomethacin.

CONCLUSIONS

Tissue synthesis of PGE(2) and LTB(4) did not correlate temporally with EHEC induced inflammation or changes in mucosal permeability and ion transport. Cyclooxygenase inhibition partially reversed ion transport abnormalities but lipoxygenase inhibition did not affect mucosal inflammation or histological damage. We conclude that the contribution of eicosanoids to mucosal injury and dysfunction is more complex than previously suggested.

Iron ore mines leachate potential for oxyradical production

The ecotoxicological effects of mining effluents is coming under much greater scrutiny. It appears necessary to explore possible health effects in association with iron ore mining effluents. The present results clearly demonstrate that iron-ore leachate is not an inert media but has the potential to induce lipid peroxidation. Peroxidation was assessed by measuring oxygen consumption in the presence of a reducing agent such as ascorbate or NADPH and a chelator such as EDTA. Labrador iron ore is an insoluble complex crystalline material containing a mixture of metals (Fe, Al, Ti, Mn, Mg,ellipsis, ) in contrast to the iron sources used for normal lipid peroxidation studies. The metal of highest percentage is iron (59. 58%), a metal known to induce oxyradical production. Iron ore powder initiated ascorbic acid-dependent lipid peroxidation (nonenzymatic) in liposomes, lipids extracted from rat and salmon liver microsomes, and intact salmon liver microsomes. It also revealed an inhibitory effect of NADPH-dependent microsomes lipid peroxidation as well as on NADPH cytochrome c reductase activity. However, nonenzymatic peroxidation in rat liver microsomes was not significantly inhibited. Cytochrome P450 IA1- and IIB1-dependent enzymatic activities as well as P450 levels were not affected. The inhibition could be due to one of the other components of iron ore leachate (Mn, Al,ellipsis, ). These effects of iron-ore leachate indicate that a potential toxicity could be associated with its release into lakes. Further studies are necessary to explore in vivo effects on aquatic animals.

Tyrosine phosphorylation: a critical component in the formation of hemidesmosomes

Our goal was to evaluate the role of tyrosine phosphorylation in the complete formation of hemidesmosomes that occurs during development or during remodeling after injury. A corneal organ culture system was used to study hemidesmosome formation as it would occur in an intact tissue. Phosphorylation of the integrin subunit beta 4 and bullous pemphigoid antigen-1 (BPAG-1) was examined, as these proteins are known to play a role in linking the electron-dense plaques along the basal surface with the intermediate filaments to complete the formation of hemidesmosomes. Corneal epithelial sheets were placed on substrata that contained an intact basal lamina or basal laminae that had been either modified or removed. These constructs were incubated for up to 18 h, and hemidesmosome formation was evaluated by using transmission electron microscopy. When epithelial sheets were placed on intact basal laminae and incubated in the presence of the tyrosine kinase inhibitor genistein (200 microM), hemidesmosome formation was impaired. The formation of electron-dense regions was delayed, and no association of intermediate filaments was detected. Results were confirmed by biochemical studies. When the epithelium and underlying proteins were extracted and immunoprecipitated with beta 4 or BPAG-1, tyrosine phosphorylation decreased in the presence of genistein. In addition, the phosphorylation of beta 4 decreased when epithelial sheets were incubated on substrata from which the basal lamina had been removed or altered. Thus, a reduction in phosphorylation of tyrosine residues impairs the formation of mature hemidesmosomes, and substrata that fail to support hemidesmosome formation also demonstrate decreased phosphorylation of tyrosine residues.

The impact of a College of Nursing Retention Program on the graduation rates of nursing students

This study was designed to measure the impact of a College of Nursing's (CON) Retention Program on students enrolled in a baccalaureate degree nursing program. Within the last ten years, undergraduate nurses increasingly have utilized the CON retention program. These students traditionally face a number of barriers to their academic endeavors. This study was designed to assess the effect of the CON program on the barriers to academic success of students who entered the CON in the Fall classes of 1991, 1992 and 1993. The sample size was 320 students. The control group consisted of 137 students who received no intervention and the experimental group was comprised of 183 students who attended intervention sessions with the Retention Coordinator in the CON. It was hypothesized that the most successful students during this period (1991-1993) were the most frequent attendees of the CON retention program intervention sessions. The alternative hypothesis was that those persons who did not attend the sessions, but were still highly persistent and successful, were enrollees who had entered with high entrance credentials as demonstrated by the transfer grade point averages (GPA). The results of this study indicated the need, use and value of this systematic approach to retention.

Improving the reproducibility of the MCF-7 cell proliferation assay for the detection of xenoestrogens

The MCF-7 cell proliferation assay is potentially a simple and highly reproducible tool for the identification of estrogenic compounds. However, its widespread use has been complicated by the lack of a standardised protocol, resulting in considerable inter-laboratory variability. We have explored the sources of variability both in relation to cell lines and test regimens and report on optimised procedures for the identification of estrogenic agents. Two supposedly identical MCF-7 parent cell lines (designated UCL and SOP), and the BUS subline were cultured according to an existing protocol, and responses to 17-estradiol (E2) assessed. Despite yielding almost identical EC50 values, the proliferative response varied widely between cell lines from 0.98-fold over controls (UCL) to 8.9-fold (BUS) indicating major differences between them. The underlying causes may be genetic, and to assess this we used comparative genomic hybridisation (CGH), a technique which allows the detection of DNA sequence copy number changes on a genome-wide scale. Although numerous similarities existed between the different cell lines, the least oestrogen-responsive line (MCF-7/UCL) exhibited the greatest number of cytogenetic changes, many of which were not seen in MCF-7/SOP cells. We suggest that care must be taken, therefore, when choosing a cell line for MCF-7 cell-based experiments. Selecting the MCF-7/SOP line for further work, we carried out a thorough and systematic optimisation of the MCF-7 cell proliferation assay, finding that a 72-h period in oestrogen-free medium before treatment strongly influenced the cells response to E2. With 1 nM E2, proliferation increased from 1.5-fold to 6.5-fold relative to vehicle-treated controls, a response similar to that seen with MCF-7/BUS cells in the E-SCREEN protocol devised by Soto et al. With parent MCF-7 cells, other laboratories have reported only 4.5-fold increases as maximal. Here we present evidence that the choice of cell line and culture conditions are crucial in determining test outcomes, and once chosen and adhered to the assay yields reproducible results.

Comparative genomic hybridization reveals extensive variation among different MCF-7 cell stocks

Comparative genomic hybridization (CGH) allows the detection of DNA sequence copy number changes on a genome-wide scale in a single hybridization reaction. The ability of CGH to be applied to formalin-fixed, paraffin-embedded tumor samples has lead to its widespread application in the cytogenetic analysis of archival material. When setting up CGH in the laboratory, rigorous control experiments must be carried out to ensure that the losses and gains are scored correctly. Groups interested in breast cancer frequently use the MCF-7 cell line as a positive control in these experiments, comparing the results to previously described genetic alterations. Here we present the results of CGH carried out with three stocks of MCF-7 cells. The cells differ widely in their proliferative response to 17-beta estradiol and show extensive variation in copy number changes affecting specific chromosomal regions. We suggest that care must be taken, therefore, when choosing a cell line as a positive control for CGH experiments.

Prevention of yeast spoilage in feed and food by the yeast mycocin HMK

The yeast Williopsis mrakii produces a mycocin or yeast killer toxin designated HMK; this toxin exhibits high thermal stability, high pH stability, and a broad spectrum of activity against other yeasts. We describe construction of a synthetic gene for mycocin HMK and heterologous expression of this toxin in Aspergillus niger. Mycocin HMK was fused to a glucoamylase protein carrier, which resulted in secretion of biologically active mycocin into the culture media. A partial purification protocol was developed, and a comparison with native W. mrakii mycocin showed that the heterologously expressed mycocin had similar physiological properties and an almost identical spectrum of biological activity against a number of yeasts isolated from silage and yoghurt. Two food and feed production systems prone to yeast spoilage were used as models to assess the ability of mycocin HMK to act as a biocontrol agent. The onset of aerobic spoilage in mature maize silage was delayed by application of A. niger mycocin HMK on opening because the toxin inhibited growth of the indigenous spoilage yeasts. This helped maintain both higher lactic acid levels and a lower pH. In yoghurt spiked with dairy spoilage yeasts, A. niger mycocin HMK was active at all of the storage temperatures tested at which yeast growth occurred, and there was no resurgence of resistant yeasts. The higher the yeast growth rate, the more effective the killing action of the mycocin. Thus, mycocin HMK has potential applications in controlling both silage spoilage and yoghurt spoilage caused by yeasts.

The nursing interventions classification: a language to define nursing

PURPOSE/OBJECTIVES

To discuss the Nursing Interventions Classification (NIC) framework and its relationship to oncology nursing.

DATA SYNTHESIS

NIC is a standardized language that identifies all interventions performed by nurses. The three-tiered taxonomy consists of six domains, 27 classes, and 433 interventions with related nursing activities. Each intervention consists of a label describing the concept, the definition of the concept, and a set of representative activities or actions.

CONCLUSIONS

Although differences exist in the core interventions identified by the Oncology Nursing Society and the Association of Pediatric Oncology Nurses as critical to their practice, the NIC research team, after surveying both organizations, found numerous similarities in the possibilities for clinical application.

IMPLICATIONS FOR NURSING PRACTICE

NIC provides a standardized language to enable oncology nurses to describe and demonstrate their work and contributions to lawmakers, healthcare policy makers, and the public.

Two alternative notions of health

Contemporary health care as well as medical ethics deal with the problem of priorities while the invariable priority of any treatment across all cultures remains health. Health as such is, however, rather a symbolic word which refers to two different paradigms coined in two ancient traditions which contributed profoundly to European culture as we know it: the two traditions referred hereto are the Hebraic and the Greek. The Greek tradition considered health as a good life, which is the utmost goal of human endeavor. To achieve this it was necessary to contemplate truth and to become acquainted with certainty (episteme) beyond any doubt. On the contrary a totally different approach can be found in the Hebraic tradition which referred particularly to faith grasped as the hope (tikva) being based on a reliance upon the future ahead. Modern medicine hesitates between these two notions of health.

Generation of PSA-ACT-specific monoclonal antibodies and their application in a sandwich immunoassay

The prostate-specific antigen (PSA) immunoassay is an important tool for the detection and monitoring of prostate cancer. PSA exists in serum mainly as complexes with serine protease inhibitors including alpha1 antichymotrypsin (ACT) and alpha2 macroglobulin (MG). PSA-MG complex is not detected by the existing PSA immunoassays since MG (720 kDa) sequesters PSA and masks the antibody binding sites. Existing immunoassays for quantitation of total serum PSA measure PSA-ACT (CPSA) and free PSA (FPSA), which comprise the major and minor components of total PSA, respectively. Monoclonal antibodies (MAb) specific for CPSA alone were generated using a unique immunogen prepared by blocking the major antigenic determinants on FPSA and ACT. The blocked immunogen greatly enhanced the frequency of hybridomas reactive against the CPSA complex. CPSA prototype immunoassays were established using anti-CPSA (PX1G359) or anti-ACT (AC1A212) MAb as tracer MAb and anti-PSA (PSA399) MAb as capture MAb. The complex-selective MAbs demonstrated minimal cross-reactivity with Cathepsin-G (CG) ACT (CG-ACT), ACT or FPSA. CG-ACT complex interfered with the accuracy of initial prototype assays specific for CPSA measurement and caused over-recovery (1 to 3 ng/mL, with 40 to 180 ng/mL range of CG-ACT in serum) of apparent CPSA values. Addition of 0.4% NP-40 and 0.1% 0.088 micron microparticles in clinical specimens eliminated this interference. Specimens from 39 prostate cancer (PCa) patients and 44 benign prostatic hyperplasia (BPH) patients were analyzed with the PX1G359 CPSA assay. In this study, the area under the curve (AUC) values for ROC analysis of total PSA (CPSA+FPSA), FPSA to total PSA ratio (f/t), and FPSA to CPSA ratio (f/c) were 0.357, 0.634, and 0.624, respectively. In a second study using AC1A212 CPSA assay, where specimens from 16 PCa patients and 48 BPH patients were tested, the AUC values for total PSA, f/t and f/c ratios were 0.62, 0.785, and 0.732, respectively. Using the CPSA assay with minimal interference our studies are consistent with previous CPSA data showing that the f/t PSA ratio remains superior to the f/c PSA ratio in differentiating PCa and BPH diseases. Complex PSA by itself or as ratio with free or total PSA does not provide any advantage over the established method of FPSA to total PSA ratio.

Shiga toxin-producing Escherichia coli can impair T84 cell structure and function without inducing attaching/effacing lesions

Enteropathogenic Escherichia coli (EPEC) intimately adhere to epithelial cells producing cytoskeletal rearrangement with typical attaching and effacing lesions and altered epithelial barrier and transport function. Since EPEC and Shiga toxin-producing E. coli (STEC) share similar genes in the "locus for enterocyte effacement" (LEE) thought to cause these changes, it has been assumed that STEC shares similar pathogenic mechanisms with EPEC. The aims of this study were to compare the effects of EPEC and STEC on bacterial-epithelial interactions and to examine changes in epithelial function. T84 monolayers were infected with STEC O157:H7 (wild strain EDL 933 or non-toxin-producing strain 85/170), EPEC (strain E2348/69), or HB101 (nonpathogenic) and studied at various times after infection. EPEC bound more avidly than EDL 933, but both strains exhibited greater binding than HB101. Attaching and effacing lesions and severe disruption to the actin cytoskeleton were observed in EPEC by 3 h postinfection but not in EDL 933 or HB101 at any time point. EPEC and EDL 933 increased monolayer permeability to [(3)H]mannitol 5- to 10-fold. In contrast to EPEC, EDL 933 completely abolished secretagogue-stimulated anion secretion as assessed under voltage clamp conditions in Ussing chambers. Several other STEC strains induced changes similar to those of EDL 933. In conclusion, STEC impairs epithelial barrier function and ion transport without causing major disruption to the actin cytoskeleton. Pathogenic factors other than products of LEE may be operant in STEC.

Visualization and functional assessment of proximal and middle left anterior descending coronary stenoses in humans with magnetic resonance imaging

BACKGROUND

Coronary artery bypass grafting improves survival in patients with >70% luminal diameter narrowing of the 3 major epicardial coronary arteries, particularly if there is involvement of the proximal portion of the left anterior descending (LAD) coronary artery. Measurement of coronary flow reserve can be used to identify functionally important luminal narrowing of the LAD artery. Although magnetic resonance imaging (MRI) has been used to visualize coronary arteries and to measure flow reserve noninvasively, the utility of MRI for detecting significant LAD stenoses is unknown.

METHODS AND RESULTS

Thirty subjects (23 men, 7 women, age 36 to 77 years) underwent MRI visualization of the left main and LAD coronary arteries as well as measurement of flow in the proximal, middle, or distal LAD both at rest and after intravenous adenosine (140 microgram/kg per minute). Immediately thereafter, contrast coronary angiography and when feasible, intracoronary Doppler assessments of coronary flow reserve, were performed. There was a statistically significant correlation between MRI assessments of coronary flow reserve and (a) assessments of coronary arterial stenosis severity by quantitative coronary angiography and (b) invasive measurements of coronary flow reserve (P<0.0001 for both). In comparison to computer-assisted quantitative coronary angiography, the sensitivity and specificity of MRI for identifying a stenosis >70% in the distal left main or proximal/middle LAD arteries was 100% and 83%, respectively.

CONCLUSIONS

Noninvasive MRI measures of coronary flow reserve correlated well with similar measures obtained with the use of intracoronary Doppler flow wires and predicted significant coronary stenoses (>70%) with a high degree of sensitivity and specificity. MRI-based measurement of coronary flow reserve may prove useful for identification of patients likely to obtain a survival benefit from coronary artery bypass grafting.

Spatial and temporal trends and effects of contaminants in the Canadian Arctic marine ecosystem: a review

Recent studies have added substantially to our knowledge of spatial and temporal trends of persistent organic pollutants and heavy metals in the Canadian Arctic marine ecosystem. This paper reviews the current state of knowledge of contaminants in marine biota in the Canadian Arctic and where possible, discusses biological effects. The geographic coverage of information on contaminants such as persistent organochlorines (OCs) (PCBs, DDT- and chlordane-related compounds, hexachlorocyclohexanes, toxaphene) and heavy metals (mercury, selenium, cadmium, lead) in tissues of marine mammal and sea birds is relatively complete. All major beluga, ringed seal and polar bear stocks along with several major sea bird colonies have been sampled and analysed for OC and heavy metal contaminants. Studies on contaminants in walrus are limited to Foxe Basin and northern Québec stocks, while migratory harp seals have only been studied recently at one location. Contaminant measurements in bearded seal, harbour seal, bowhead whale and killer whale tissues from the Canadian Arctic are very limited or non-existent. Many of the temporal trend data for contaminants in Canadian Arctic biota are confounded by changes in analytical methodology, as well as by variability due to age/size, or to dietary and population shifts. Despite this, studies of OCs in ringed seal blubber at Holman Island and in sea birds at Prince Leopold Island in Lancaster Sound show declining concentrations of PCBs and DDT-related compounds from the 1970s to 1980s then a levelling off during the 1980s and early 1990s. For other OCs, such as chlordane, HCH and toxaphene, limited data for the 1980s to early 1990s suggests few significant declines in concentrations in marine mammals or sea birds. Temporal trend studies of heavy metals in ringed seals and beluga found higher mean concentrations of mercury in more recent (1993/1994) samples than in earlier collections (1981-1984 in eastern Arctic, 1972-1973 in western Arctic) for both species. Rates of accumulation of mercury are also higher in present day animals than 10-20 years ago. Cadmium concentrations in the same animals (eastern Arctic only) showed no change over a 10-year period. No temporal trend data are available for metals in sea birds or polar bears. There have been major advances in knowledge of specific biomarkers in Canadian Arctic biota over the past few years. The species with the most significant risk of exposure to PCBs and OC pesticides may be the polar bear which, based on comparison with EROD activity in other marine mammals (beluga, ringed seal), appears to have elevated CYP1A-mediated activity. The MFO enzyme data for polar bear, beluga and seals suggest that even the relatively low levels of contaminants present in Arctic animals may not be without biological effects, especially during years of poor feeding.

Enhancing clinical pathway placement

Soaring health care costs have fueled the immense growth in managed care. To contain these costs, health care organizations have turned to clinical pathways. However, clinical pathways cannot do an effective job if health care personnel are not aware of their existence. The article presents a simple, effective, and efficient method to increase placement of clinical pathways in inpatient medical records.

4-hydroxycinnamoyl-CoA hydratase/lyase (HCHL)--An enzyme of phenylpropanoid chain cleavage from Pseudomonas

The enzyme 4-hydroxycinnamoyl-CoA hydratase/lyase (HCHL), which catalyzes a hydration and two-carbon cleavage step in the degradation of 4-hydroxycinnamic acids, has been purified and characterized from Pseudomonas fluorescens strain AN103. The enzyme is a homodimer and is active with three closely related substrates, 4-coumaroyl-CoA, caffeoyl-CoA, and feruloyl-CoA (Km values: 5.2, 1.6, and 2.4 microM, respectively), but not with cinnamoyl-CoA or with sinapinoyl-CoA. The abundance of the enzyme reflects a low catalytic center activity (2.3 molecules s-1 at 30 degrees C; 4-coumaroyl-CoA as substrate).

Healthcare in Japan: its professionals, institutions, and financing

Like the United States, Japan's healthcare system is a conglomerate of government, employer, and individual financing--but that's about as far as the similarity goes. Universal access to basic healthcare has been achieved in Japan through comprehensive employer/employee plans and government subsidies. However, the United States should not be too hasty in emulating Japan, for culture plays a definite role in healthcare on both sides of the Pacific.

Using multiple response true-false multiple choice questions

The Royal Australasian College of Surgeons (RACS) Board of Examiners, having agreed to replace Type K with Type X multiple choice questions (MCQ), undertook a study to determine the most appropriate method of scoring the latter. Retrospective scoring of candidates' responses in a previous examination, using six reported scoring techniques for Type X items, showed that the Middlesex technique yielded a mean score closest to the mean score of the Type K items which were being replaced. However, as candidates' responses are affected by instructions, and the latter could not be controlled, a prospective study was carried out on three examinations, in each of which the nature of Part C varied among the three papers, while Parts A and B were similar. Paper 1 contained Type K items in Part C, Paper 2 contained Type X items with instructions appropriate for the Middlesex technique, and Paper 3 contained Type X items scored +1 if correct, -1 if incorrect and 0 if omitted. Items sampling the same content areas were randomly distributed among the three papers. The results indicated that the two Type X systems yielded significantly lower mean scores than Type K, probably due to combinations characteristic of the latter, enabling candidates with partial knowledge to obtain a maximum score. The difference in mean scores between the two Type X systems was not significant. A significantly higher mean percentage score in reused Type X (Middlesex system) items over that of the same items when they were previously used as Type K items was attributed to the combined effects of credit for partial knowledge, practice on reused items and differences in mean candidate ability across years. Pearson product-moment correlation coefficients between pairs of Part C mean percentage scores at each examination were positive and significant. The Board decided to replace Type K with Type X items, and the +1, 0, -1 system of scoring was adopted as it was considered more efficient than the Middlesex system, which did not give credit for identifying false statements as false.

A role for the hepatobiliary system in IgE-mediated intestinal inflammation in the rat

BACKGROUND

For many years the central focus of research into gastrointestinal hypersensitivity reactions has been the mast cell population of the intestinal lamina propria. Since bile is known to deliver immunological mediators to the gastrointestinal tract, the possibility arises that extra-intestinal populations of mast cells may also contribute to IgE-mediated intestinal damage.

OBJECTIVES

To characterize hepatic mast cells in the rat and to investigate the role of the hepatobiliary system in a model of IgE-mediated reactivity to dietary antigen.

METHODS

Wistar rats were passively sensitized with monoclonal antidinitrophenyl (DNP) IgE antibodies, and were later challenged orogastrically with DNP-HSA. Additional animals were sensitized, then bile duct-cannulated prior to antigen challenge. At various time points, liver and intestinal samples were collected for histological examination, and bile was collected and assayed for histamine and TNFalpha.

RESULTS

Hepatic mast cells display a mucosal mast cell-like phenotype, and are closely associated with the vessels of the portal triads. Orogastric antigen challenge led to a rapid and significant decline (P<0.0001) in detectable mast cells as a result of anaphylactic degranulation. The median number of granulated mast cells associated with each portal triad in liver sections declined from six per portal triad to one per portal triad post-antigen challenge. After 15 min, biliary histamine concentrations rose above background levels (P<0.01). TNFalpha was also detectable in the majority (4/6) of bile samples within 15 min of challenge. Histological examination of the gastrointestinal mucosa revealed disruption to the villous epithelium ranging from oedematous changes to gross destruction. Such damage was not seen in animals in which bile had been externally drained.

CONCLUSION

The data indicate that biliary products are major contributors to the gastrointestinal damage arising from IgE-mediated hypersensitivity reactions in the rat, and such hypersensitivity reactions may involve a population of mast cells which reside in the liver.

Relationship of cognitive and functional impairment to depressive features in Alzheimer's disease and other dementias

Patients with clinical diagnoses of Alzheimer's disease, vascular dementia, or undifferentiated dementia were rated on standardized measures of depression, cognitive impairment, and functional impairment. Logistic regression was used to evaluate the relationship between functional or cognitive impairment, as well as their interaction, and depressive features in each group. This analysis revealed notable differences by type of dementia. The results imply that the mechanisms underlying depression in Alzheimer's disease may be different from those in vascular and other types of dementia. These results also provide indicators to the clinician for further evaluation of depression in different dementia subtypes.