Prioritizing testing of organic compounds detected as gas phase air pollutants: structure-activity study for human contact allergens

Organic compounds that are used or generated anthropogenically in large quantities in cities can be identified through their presence in the urban atmosphere and in air pollutant source emissions. Compounds identified by this method were screened to evaluate their potential to act as contact allergens. The CASE and MULTICASE computer programs, which are based on the detection of structure-activity relationships (SAR), were used to evaluate this potential. These relationships first are determined by comparing chemical structures to biological activity within a learning set comprised of 458 compounds, each of which had been tested experimentally in human trials for its sensitization potential. Using the information contained in this learning set, CASE and MULTICASE predicted the activity of 238 compounds found in the atmosphere for their ability to act as contact allergens. The analysis finds that 21 of 238 compounds are predicted to be active contact allergens (probability >0.5), with potencies ranging from mild to very strong. The compounds come from chemical classes that include chlorinated aromatics and chlorinated hydrocarbons, N-containing compounds, phenols, alkenes, and an S-containing compound. Using the measured airborne concentrations or emission rates of these compounds as an indication of the extent of their use, together with their predicted potencies, provides an efficient method to prioritize the experimental assessment of contact sensitization of untested organic compounds that can be detected as air pollutants.

Stimulus responses and amyloid precursor protein processing in DAMI megakaryocytes

Platelets, when released as anuclear cells by their precursor megakaryocytes, already carry soluble proteolytic fragments of the amyloid precursor protein (APP) within their alpha-granules and intact APP in the alpha-granule membranes. In response to activation signals elicited by physiologic stimuli such as thrombin, platelets release their granules' soluble contents and translocate granule membrane-bound proteins to the plasma membrane. Because platelets carry >90% of the circulation's APP, activated platelets have been implicated as origins of the beta-amyloid peptide fragment of APP (A beta), whose deposition in the cerebrovasculature is characteristic of Alzheimer's disease. We have therefore studied the APP contents and proteolytic processing in resting DAMI human megakaryocytic cells, along with the consequences of the activation of these cells by thrombin, comparing the results in each case to those with human platelets. Resting and PMA-differentiated DAMI cell contents were examined by Western blotting, immunoprecipitation, or metabolic labeling with sulfur 35-labeled methionine during culture, while plasma membrane-bound APP was evaluated by flow cytometry. Activation was followed by changes in cytoplasmic calcium concentration ((Ca++)in) and in membrane potential. Like platelets, DAMI cells exhibited a thrombin dose-dependent delta(Ca++)in, and membrane potential change; in contrast to the surface of a platelet, the surface of an agranular resting DAMI cell expresses granule-membrane proteins (APP and CD63) that appear on platelets only after activation. DAMI cell culture with 35S-labeled methionine confirmed that megakaryocytes synthesize large amounts of APP, of slightly higher molecular weight, and degrade their APP extensively before platelets are formed.

Craniad migration of differing doses of new methylene blue injected into the epidural space after death of calves and juvenile pigs

OBJECTIVE

To determine the relation between epidural injectate volume (ml/kg of body weight) and its craniad migration in calves and pigs.

ANIMALS

23 neonatal calves and 26 feeder pigs.

PROCEDURE

Animals were randomly assigned to receive different volumes of new methylene blue (NMB, 1.2 mg/ml in 0.9% saline solution). Injections were made into the sacrococcygeal intervertebral space in calves and the lumbosacral intervertebral space in pigs, immediately after euthanasia. Sagittal sections of the spine were made at necropsy, and craniad migration of NMB was determined and rounded to the nearest intervertebral space.

RESULTS

In calves treated with 0.05, 0.1, or 0.15 ml of NMB/kg, mean +/- SEM number of stained spinal segments was 5 +/- 0.3, 8 +/- 0.6, and 8 +/- 0.6, respectively. Craniad migration of NMB was significantly greater for 0.15 and 0.1 ml/kg volumes versus 0.05 ml/kg. In pigs treated with 0.05, 0.1, 0.2, of 0.3 ml of NMB/kg, mean number of stained spinal segments was 8 +/- 1.1, 8 +/- 0.9, 10 +/- 1.2, and 18 +/- 2.0. Craniad dye migration was significantly greater in the 0.3 ml/kg group versus the 3 lower volume groups. Linear regression performed on both sets of data after logarithmic transformation of spaces migrated to correct for non-normality was significant (P < 0.05), and R2 values of 0.49 and 0.55 were obtained for calves and pigs, respectively.

CONCLUSIONS

There is a significant correlation between volume (ml/kg) of NMB injected in the epidural space and its craniad migration in calves and pigs.

CLINICAL RELEVANCE

Results provide a basis for determination of volume of injectate to be given to reach a minimal desired level and should be a useful baseline for future investigations of epidural drug administration.

Fit of veneers made by CAD-CAM and platinum foil methods

Veneers were fabricated by CEREC CAD-CAM and the platinum foil techniques for standardized preparations on 10 artificial teeth. Mesial preparation contacts were broken, but distal contacts remained intact. The veneers were cemented in a standardized manner to their teeth. The veneers and their attached cement were embedded in epoxy resin and sectioned twice gingivally-incisally and mesially-distally to produce eight sections. Three-way ANOVA disclosed that the main effects of fabrication method, section location, and measurement point location as well as all interaction terms significantly affected fit (P < 0.05). However, the difference in mean overall fit between the fabrication methods was too small to be of clinical importance. Restoration of the broken approximal contact did not compromise fit. Incisal margins had the greatest marginal openings. Surface measurement point locations were less well adapted than internal locations. Fit maps for CEREC and platinum foil veneers were strikingly similar.

Eagle's syndrome (elongated styloid process)

Eagle's syndrome occurs when an elongated styloid process or calcified stylohyoid ligament causes recurrent throat pain or foreign body sensation, dysphagia, or facial pain. Additional symptoms may include neck or throat pain with radiation to the ipsilateral ear. In adults, the styloid process is approximately 2.5 cm long, and its tip is located between the external and internal carotid arteries, just lateral to the tonsillar fossa. It may develop inflammatory changes or impinge on the adjacent arteries or sensory nerve endings, leading to the symptoms described. Diagnosis can usually be made on physical examination by digital palpation of the styloid process in the tonsillar fossa, which exacerbates the pain. In addition, relief of symptoms with injection of an anesthetic solution into the tonsillar fossa is highly suggestive of this diagnosis. Radiographic workup should include anterior-posterior and lateral skull films. The treatment of Eagle's syndrome is primarily surgical. The styloid process can be shortened through an intraoral or external approach. We present two cases and review the literature.

Physical activity related energy expenditure and fat mass in young children

OBJECTIVE

To examine whether body fat content in pre-pubertal children is influenced by physical activity related energy expenditure (AEE) and/or more qualitative aspects of physical activity.

DESIGN

Cross-sectional study.

SUBJECT

101 pre-pubertal children were examined in Study 1: (age: 5.3 +/- 0.9 y; weight: 20.2 +/- 3.6 kg). In Study 2: 68 of the original children were re-examined (age: 6.3 +/- 0.9 y; weight: 23.6 +/- 5.0 y).

MEASUREMENT

Fat mass (FM) and fat free mass (FFM) were determined by bioelectrical resistance and skinfolds; AEE was estimated from the difference between total energy expenditure (TEE) by doubly labeled water and post-prandial resting energy expenditure (REE) by indirect calorimetry; qualitative information on activity was derived by questionnaire.

RESULTS

AEE was significantly correlated with FFM (r = 0.32 in both Studies) and body weight (r = 0.28 in Study 1; r = 0.29 in Study 2), but not FM. There were no significant relationships between AEE and any of the variables from the activity questionnaire in children (including TV time, playing time, and an accumulated activity index in h/week). After adjusting for FFM, age, and gender, FM was inversely related to activity time in h/week (partial r = -0.24 in Study 1; partial r = -0.32 in Study 2) but not AEE (P > 0.5).

CONCLUSION

After adjusting for FFM, age, and gender, a small portion of the variance in body fat mass in children (approximately 10%) is explained by time devoted to recreational activity, whereas none of the variance is explained by the combined daily energy expenditure related to physical activity.

A system for mutation measurement in mammalian cells: application to gamma-irradiation

Monitoring of mutagenesis by environmental agents for the purpose of preventing genetic disease including cancer must include quantitation of cell killing, sensitive measurement of mutation production by appropriate doses of each agent, and assessment of mutation repair effects in mammalian cells. A four-step procedure, in the presence and absence of a repair suppressor, is proposed: (i) determination of the survival curve; (ii) measurement of the mitotic index in cells collected after treatment with colcemid; (iii) construction of a mutagenesis yield curve in the presence and absence of a repair suppressor, like caffeine; and (iv) assessment of the effect of test agents on the repair of mutations produced by other mutagens. The procedure is quantitative, reproducible, and reasonably rapid. It involves measurement of mutations causing visible chromosomal aberrations. Numerical parameters are proposed defining quantitatively mutation, cell killing, and mutation repair capacity. The procedure is applied to gamma-irradiation and can detect the effects of doses as low as 2-5 cGy. Theoretical analysis of the underlying processes is presented, using the concept of D(0)E, the effective dose of mutagen after repair mechanisms and neutralizing agents have acted. Microscopically visible chromosome aberrations are due to mutations that distort the process of mitotic chromosome condensation, with or without actual chromosome breakage.

Tolerance of mefloquine by SwissAir trainee pilots

Due to presumed adverse performance impact, a World Health Organization clause currently restricts the use of mefloquine malaria chemoprophylaxis in individuals requiring fine coordination and spatial discrimination. We conducted a double-blind, placebo-controlled, cross-over study to quantitatively assess the effects of mefloquine at steady state on performance in 23 trainee airline pilots. Flying performance was assessed using a flight simulator, psychomotor function was evaluated, sleep and wake cycles were monitored, and symptoms and moods were assessed using standardized questionnaires. A simplified postural sway meter recorded sway in three test positions. In the mefloquine loading dose phase, there was one withdrawal due to dizziness, diarrhea, and flu-like symptoms, and three volunteers reported nonserious, sleep-related adverse events. There was no significant difference in flying performance, psychomotor functions, or mean sway for any test position. Nonsignificant reductions in mean total nocturnal sleep (mefloquine = 450 min versus placebo = 484 min) and poorer sleep quality were detected in the mefloquine phases. The mood findings indicated a predominance of positive states, with vigor the predominant mood in all phases. No significant performance deficit was documented under laboratory conditions during use of mefloquine at steady state.

Dehydroepiandrosterone (DHEA) treatment of depression

Dehydroepiandrosterone (DHEA) and its sulfate, DHEA-S, are plentiful adrenal steroid hormones that decrease with aging and may have significant neuropsychiatric effects. In this study, six middle-aged and elderly patients with major depression and low basal plasma DHEA f1p4or DHEA-S levels were openly administered DHEA (30-90 mg/d x 4 weeks) in doses sufficient to achieve circulating plasma levels observed in younger healthy individuals. Depression ratings, as well as aspects of memory performance significantly improved. One treatment-resistant patient received extended treatment with DHEA for 6 months: her depression ratings improved 48-72% and her semantic memory performance improved 63%. These measures returned to baseline after treatment ended. In both studies, improvements in depression ratings and memory performance were directly related to increases in plasma levels of DHEA and DHEA-S and to increases in their ratios with plasma cortisol levels. These preliminary data suggest DHEA may have antidepressant and promemory effects and should encourage double-blind trials in depressed patients.

Multiple visuospatial working memory buffers: evidence from spatiotemporal patterns of brain activity

Numerous studies have shown that the visual system involves different cortical pathways in the perception of object (ventral visual pathway) and spatial (dorsal visual pathway) information. The present study was concerned with whether human visuospatial working memory divides along similar lines. We used event-related brain potentials (ERPs) recorded from scalp of normal humans to show the existence of different buffering systems for the retention of object and spatial visual information. Subjects were presented with object or spatial stimuli to be retained for a 3.6-sec interval. The ERPs isolated brain activity associated with retention from earlier storage and later retrieval processes. The ERP scalp topographies indicated that the underlying patterns of brain activation were different during retention of object and spatial information.

Effect of fit adjustment on CEREC CAD-CAM veneers

PURPOSE

To measure and compare the adaptation of CEREC CAD-CAM porcelain veneers with and without fit adjustment.

MATERIALS AND METHODS

Two groups of porcelain veneers were fabricated using the CEREC CAD-CAM technique for standardized preparations on 10 artificial teeth. Mesial preparation contacts were broken, but distal contacts remained intact. One group was adjusted using a disclosing spray to improve fit, another group made for the same teeth was not adjusted before cementation. The veneers were cemented in a standardized manner to their teeth. The veneers and their attached cement were retrieved, embedded in epoxy resin and sectioned twice to produce eight sections. Each section was measured at three defined points from the external surface inwards.

RESULTS

Three-way ANOVA disclosed that fit adjustment was relatively ineffective (P approximately 0.05), but that measurement section location, measurement point location and their interaction significantly affected fit (P < 0.05). Restoration of the broken proximal contact, or simulated diastema closure did not compromise fit. Incisal margins ranked worst for fit. Surface measurement point locations ranked worse than internal points. The fit of these CEREC CAD-CAM veneers was not substantially different from previously published fit values for conventional porcelain veneers.

Genetic relationships among production traits and rebreeding performance

We studied effects of selection for increased daily gain, reduced backfat, increased number of piglets born alive, and increased 21-d litter weight on interval from weaning to farrowing (IWF) of two commercial populations of purebred Large White (LW) and Landrace (LR) lines with each represented in two farms. The analysis took into account that normal and prolonged intervals could be distinguished. Distributions of IWF were described by a mixture of a normal and an exponential distribution. Observed intervals were transformed to the probability of being a prolonged interval, using the mixed density function. Incidence of normal intervals was less in LR than in LW sows and was least in first-litter sows. Heritability estimates of IWF ranged from zero to .24 across parities and farms. Genetic trend within breed and farm was different from zero (P < .05) for each trait under selection, except backfat on Farm 2. Genetic correlations between the traits under selection and IWF were inconsistent across farms. Differences in estimated breeding value for the traits under selection between sows with a normal and a prolonged interval were significant only on Farm 1 in the Large White breed, when only observed intervals were analyzed. Including culled sows in the analysis as sows with a prolonged interval yielded consistent differences for average daily gain and backfat, such that genetic selection for improved production would increase the liability for a prolonged interval. Culling sows for delayed estrus apparently overcame this problem on Farm 2 but not on Farm 1, on which a trend of increasing incidence of prolonged intervals was observed.

Effects of simvastatin and enalapril on serum lipoprotein concentrations and left ventricular mass in patients on dialysis. The Perfect Study Collaborative Group

A randomised trial of simvastatin and enalapril in patients with chronic renal failure on dialysis: effects on serum lipoprotein concentrations and left ventricular mass. Left ventricular hypertrophy and abnormalities of lipoprotein metabolism are both possible contributors to the high risk of cardiovascular death in patients with chronic renal failure on dialysis. We investigated the effects of simvastatin on lipid and lipoprotein concentrations and the effects of enalapril on left ventricular mass in 107 patients receiving haemodialysis or continuous ambulatory peritoneal dialysis. Patients were randomised in a factorial design to receive simvastatin (10 mg daily) or placebo and enalapril (2.5-5 mg daily) or placebo. During follow-up, there was a significant excess of patients withdrawn from enalapril because of hypotension (2p = 0.002), and after 6 months only 55% of those assigned enalapril were still on treatment. From baseline to 6 months, there were no statistically significant differences in left ventricular mass or left ventricular dimensions between patients assigned enalapril and those assigned placebo. Among the patients assigned simvastatin, total cholesterol was reduced by 13% (2p = 0.001), LDL cholesterol was reduced by 17% (2p = 0.003) and apolipoprotein B was reduced by 12% (2p = 0.005) compared to patients assigned placebo. There were borderline significant (2p = 0.05 to 0.08) reductions in VLDL cholesterol, total triglyceride and VLDL triglycerides of 26%, 12% and 17% respectively. Large-scale trials are now required to determine whether reductions in lipid and lipoprotein concentrations confer a reduction in coronary heart disease morbidity and mortality in patients on dialysis.

Synthesis, in vitro antiviral evaluation, and stability studies of bis(S-acyl-2-thioethyl) ester derivatives of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA) as potential PMEA prodrugs with improved oral bioavailability

A new series of hitherto unknown 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA) phosphonodiester derivatives incorporating carboxyesterase-labile S-acyl-2-thioethyl (SATE) moieties as transient phosphonate-protecting groups was prepared in an attempt to increase the oral bioavailability of the antiviral agent PMEA. We report here a direct comparison of the in vitro anti-HIV and anti-HSV activities as well as the in vitro stability between the bis(SATE) derivatives and the already known PMEA prodrugs, namely, bis[(pivaloyloxy)methyl (POM)]- and bis[dithiodiethyl (DTE)]PMEA. All of the compounds tested showed an enhanced in vitro antiviral activity compared to the parent PMEA. The bis(POM)- and bis(tBu-SATE)PMEA derivatives were the most effective. However, striking differences between these two compounds were found during the stability studies. In particular the bis(tBu-SATE)PMEA was found to be more stable than bis(POM)PMEA in human gastric juice and human serum, suggesting it could be considered as a promising candidate for further in vivo development.

Differential expression of bone morphogenetic proteins in the developing vestibular and auditory sensory organs

The genes responsible for the formation of various sensory organs in the inner ear are not known. There are eight sensory organs in the chick inner ear, and our previous study showed that all presumptive sensory organs initially express bone morphogenetic protein 4 (BMP4), a member of the transforming growth factor (TGF)-beta gene family. To address the potential role of BMPs in the patterning of different sensory organ structures, we investigated the expression of BMP4, BMP5, and BMP7 during sensory organ differentiation in the chick inner ear. The gene expression pattern of BMP5, although similar to that of BMP4, was transient and disappeared by embryonic day 3.5 (E3.5). In contrast, BMP7 gene expression was quite extensive, starting in the otic placode. By E5, gene expression patterns of BMP4 and BMP7 differed among vestibular and auditory sensory organs. In the vestibular sensory organs, BMP7 gene expression segregated from the main sensory tissue areas at the onset of differentiation, whereas BMP4 expression concentrated in supporting cells. In the cochlea, however, BMP7 gene expression became restricted to sensory tissue over time and eventually concentrated in supporting cells, whereas BMP4 gene expression was localized to hair cells. The different BMP expression patterns in developing auditory and vestibular sensory organs may help to shape each respective sensory structure. Furthermore, the expression of BMP4 in the cochlea also revealed an interesting pattern of sensory cell differentiation: the distal portion of the cochlea differentiates first, and the tall hair cells develop before the short hair cells.

Pre-operative health screening for total knee replacement

One hundred patients on the waiting list for total knee replacement at the Wirral Hospitals underwent a domiciliary pre-operative assessment with the rheumatology clinical nurse specialist. As a result of this assessment the operations of 31 of the 100 patients were postponed and seven were cancelled because of a variety of medical and surgical problems. All patients, when eventually admitted, underwent their surgery on the appointed date with no further postponements.

Custody and caring: clinical placement of student nurses in a forensic setting

TOPIC

Clinical placement of student nurses in a forensic setting during their psychiatric nursing course.

SOURCE

Curriculum at the College of Nursing, University of Saskatchewan.

GOAL

To describe a unique setting for learning psychiatric nursing.

CONCLUSION

Forensic settings provide an opportunity for students nurses, educators, and clinicians to work together to learn and to provide excellent care.