Evaluation of the Digene Hybrid Capture System for detection and quantitation of human cytomegalovirus viremia in human immunodeficiency virus-infected patients

The Digene Hybrid Capture System (DHCS) is a solution hybridization antibody capture assay for the chemiluminescent detection and quantitation of cytomegalovirus (CMV) DNA in leukocytes. This assay was compared with the CMV antigenemia assay and shell vial and tube cultures for the detection of CMV in 234 blood specimens from 72 patients with human immunodeficiency virus. Intra- and interrun precision of the DHCS assay gave coefficients of variation of 17.8 and 16.3%, respectively. The correlation coefficient for the quantitative results obtained by the DHCS assay and the antigenemia assay was 0.911 (95% confidence interval, 0.885 to 0.930). Agreement between the DHCS assay and the other three assays ranged from 83 to 86%. The DHCS assay detected 71, 87, and 84% of specimens that were positive by antigenemia, shell vial cultures, and tube culture, respectively. A total of 92% of specimens that were positive by the DHCS assay were also positive by at least one of the other assays. Evaluation of the usefulness of quantitation of CMV DNA by using the DHCS assay and its correlation with clinical disease demonstrated that, with some exceptions, patients with clinical CMV disease tended to have high levels of DNA whereas asymptomatic patients tended to have low or undetectable levels. Overall, the DHCS assay provided a rapid, quantitative, and objective measure of CMV activity in leukocytes, but results did not always correlate with clinical disease.

A mucopyocele of the clivus: case report

OBJECTIVE AND IMPORTANCE

There are increasing reports of nasal sinus mucopyoceles eroding the base of the cranium and causing the rapid onset of neurological complications. Uncommon presentations can mimic tumors, but the infectious nature mandates an urgent surgical decompression. It is important to document these uncommon presentations. CLINICIAL PRESENTATION: A mucopyocele of the clivus is reported in a patient with a frequent history of sinusitis. Diplopia caused by an acute sixth nerve palsy prompted the radiological diagnosis with computed tomography and magnetic resonance imaging.

INTERVENTION

Transsphenoidal drainage of the lesion lead to marked improvement in the patient.

CONCLUSION

This is the third reported case of a clival mucocele. Mucoceles of nasal sinuses can erode intracranially, causing neurological sequalae, and clival involvement is extremely rare. Early drainage leads to marked improvement.

Retro-retinoids in regulated cell growth and death

Vitamin A serves as a prohormone from which three classes of active metabolites are derived: the aldehydes, the carboxylic acids, and the retro-retinoids. Although these three classes are united under the rubric of signal transduction, they act by different molecular mechanisms: the 11-cis-retinaldehydes combine with opsin to form the universal visual pigments and the retinoic acids form ligands for transcription factors, whereas the retro-retinoids, as shown here, intersect with signal transduction at a cytoplasmic or membrane site. The retro-retinoid, anhydroretinol (AR), has long been known to act as a growth inhibitor in lymphocytes, whereas 14-hydroxy-4,14-retro-retinol (14-HRR) is required for normal lymphocyte proliferation. A mutually reversible relationship exists between these two retro-retinoids as one can reverse the effects of the other when given in pharmacological doses. The common explanation for reversible inhibition is competition for a shared receptor. We now provide evidence that when AR is given to T cells unmitigated by 14-HRR, rapid cell death can occur. The circumstances are closely related to nonclassical forms of apoptosis: within 2 h of AR administration the T cells undergo widespread morphological changes, notably surface blebbing and ballooning and, inevitably, bursting. In contrast, nuclear changes are comparatively mild, as indicated by absence of chromatin condensation and overt DNA cleavage to discrete nucleosomal fragments, although DNA nicks are readily discernible by terminal deoxynucleotidyl transferase assay. What further distinguishes the AR-induced form of apoptosis from classical ones is a lack of requirements of messenger RNA and protein synthesis, suggesting that the events leading to cell death are primarily initiated and play themselves out in the cytoplasm. This view is further reinforced by the finding that herbimycin A can prevent the onset of programmed cell death. The importance of our findings is that they strongly suggest a second messenger role for vitamin A metabolites in the cytoplasmic realm that has not been seen previously. These findings are entirely compatible with a general notion that in a cell requiring multiple coordinated signals for survival, the provision of an unbalanced signal can initiate programmed cell death. Collectively, our data also challenge the paradigm that retinoids (outside vision) solely mediate their function via the steroid/ retinoic acid receptor family of nuclear transcription factors. Instead, a mode of action in the cytoplasmic realm akin to one attributed to other small lipophilic second messenger molecules, such as diacyl glycerol or ceramide, may apply to retro-retinoids.

The influence of target perturbation on manual aiming asymmetries in right-handers

Ten right-handed subjects performed 100 target-aiming movements with each hand. These movements were directed toward a small target on the midline. On 60% of the trials, the target remained stationary. On other randomly placed trials, the target "jumped" to a location 3 cm to the right (20%) or left (20%) of its original position when the cursor had travelled 6.5 cm. Although no hand differences were evident in the control condition, the right hand acquired the new target location more quickly than the left hand when the target was perturbed in either direction. Kinematic data revealed that this advantage was not due to initiating an adjustment to the initial movement more rapidly, but rather less time decelerating the corrective movement. Movement adjustments on perturbed trials were implemented more rapidly in left space than right space independent of the hand doing the aiming. These asymmetries may reflect the differential role of the two cerebral hemispheres in the control of goal-directed movements.

Contributions of experience to the development of musical processing in infancy

Full-term infants' performance in detection of melodic alterations appeared to be influenced by perceptual experience from 6 months to 1 year of age, and an experiment with infants born prematurely supported the hypothesis that experience affects music processing in infancy. These findings suggest parallel developmental tendencies in the perception of music and speech that may reflect general acquisition of perceptual abilities for processing of complex auditory patterns. This acquisition may contribute to the cultural enfranchisement of infants through perceptual experience.

13,14-Dihydroxy-retinol, a new bioactive retinol metabolite

Deprivation of vitamin A (retinol) leads to reduced potential of B cell proliferation and nearly complete block of T cell activation in vitro. Retinol, which is thought to function as a pro-hormone, is enzymatically converted into intracellular messenger molecules. Thus, 14-hydroxy-retro-retinol (14-HRR) is an intracellular messenger molecule linked to activation and growth regulation of lymphocytes; whereas, anhydroretinol, another natural retro-retinoid, is an antagonist of 14-HRR effects. In this article, we describe the isolation, structure determination, synthesis, and biological properties of a new intracellular retinol derivative, 13,14-dihydroxy-retinol (DHR), which also supports the viability of retinol-deprived lymphocytes. DHR is found in numerous cell lines representing a large cross-section of tissues and animals from insects to mammals. In T lymphocytes the production of DHR and 14-HRR is up-regulated by phorbol ester. DHR is converted to 14-HRR by mild acid treatment, but not by cells; therefore DHR is not a biosynthetic intermediate in the conversion of retinol to 14-HRR. DHR is a distinct end point of retinol metabolism. Although it is linked to cell proliferation, its biological role remains to be determined.

The preparation of aiming movements

Three experiments are reported in which subjects made rapid aiming movements to visual targets with their left and right hands. In Experiments 1 and 3, a precue protocol was employed. In the "simple" reaction time condition, subjects were precued with complete information concerning the target position. In the four-choice condition, subjects were precued with partial information, indicating a subset of four possible target positions. In the eight-choice condition, advance information regarding the target position was entirely ambiguous. Results indicated that when subjects were provided with unspecific advance information concerning the position of the target, and thus were unable to partially prepare movements prior to the imperative stimulus, a left hand advantage for speed of initiation was obtained. When complete advance information was available, reaction times for the left and right hands were equivalent. The left hand advantage in choice conditions was eliminated when the accuracy of response execution was emphasized and subjects were afforded the opportunity for "on-line" preparation (Experiment 3). These data are discussed in relation to the role of the right hemisphere in the preparation of movement.

Intermittent vision and discrete manual aiming

This study was designed to assess how the precision requirements of discrete aiming movements affect the utility of brief visual samples provided during execution of movement. Subjects pointed with a hand-held stylus to targets with indices of difficulty of 3, 4, 5, and 6 bits with full vision, no vision, and in conditions in which 20-msec. visual samples were provided every 80, 140, or 200 msec. While intermittent vision required slightly longer movement times for targets with a high index of difficulty, subjects' accuracy was similar to the full-vision situation. Moreover, with intermittent vision, the movement trajectories resembled the full-vision and not the no-vision situation. It would appear that brief visual samples of the movement environment are sufficient for reasonably precise closed-loop control.

Asymmetries in Coupling Dynamics of Perception and Action

The influence of information-based dynamics on coordination dynamics of rhythmic movement was examined with special reference to the expression of asymmetries. In Experiment 1, right-handed subjects performed unimanual, rhythmical movements in coordination with either a discrete or continuous visual display. The right hand-visual display system defined a more stable perception-action collective than the left, particularly when continuous visual information was available. In Experiment 2, the same subjects performed rhythmic bimanual movements in coordination with a continuous visual display. The action collective was inherently more stable than the perception-action collective, although similar patterns were observed at both levels. Importantly, the dynamics of the perception-action collective impinged upon the dynamics of the action collective in terms of stability. Asymmetries remained evident between limbs in the bimanual preparations, with the left hand exhibiting greater limit-cycle variability and also a tendency to more often effect transitions at the action couple. Features of dynamical models that capture characteristics of manual asymmetries are discussed.

Cerebral specialization for spatial processing in adults with Down syndrome

Cerebral specialization for spatial processing in adults with Down syndrome was examined. In the first experiment, both control and right-handed subjects with Down syndrome exhibited no lateral advantage in a dihaptic shape-matching task, whereas left-handed subjects with Down syndrome displayed an expected left-hand advantage. In a visual field dot enumeration task in the second experiment, all groups exhibited left-field superiority. Thus, atypical cerebral organization of function in adults with Down syndrome appears to be confined to speech perception (Elliott & Weeks, 1993).

Evaluation of the automated vitek immunodiagnostic assay system (VIDAS) for the detection of measles (rubeola) IgG antibodies,

BACKGROUND

The VIDAS MSG assay is a rapid, automated assay system for the detection of measles antibodies which has not yet been fully evaluated.

OBJECTIVES

To compare the VIDAS MSG assay with hemagglutination inhibition (HAI) and a commercial enzyme immunoassay (EIA) for the determination of measles immune status.

STUDY DESIGN

Four hundred and seventy-seven serum samples collected from hospital employees for pre-employment screening were tested for measles antibodies using the VIDAS MSG assay and the results compared with those obtained by HAI and EIA. Intra-and inter-assay precision runs of the VIDAS instrument were evaluated using the positive standard provided by the manufacturer.

RESULTS

The sensitivity of the VIDAS assay compared to HAI and EIA was 96.4% and 96.7%, respectively. The specificity of the VIDAS assay, when grouping equivocal with negative results was 77.6% and 100% compared to HAI and EIA respectively. The co-efficient of variation for both precision runs was less than 10%, indicating good reproducibility.

CONCLUSIONS

The VIDAS MSG assay system is rapid and less labour intensive than HAI and manual EIA for the detection of measles antibody. The significance of equivocal results is not known, but may represent low, non-protective antibody levels. Testing of equivocal samples using another test may provide a definitive (positive or negative) result, but the degree of protection afforded by a positive result is not known. Alternatively, equivocals may be grouped with negatives for exposure or vaccination purposes. This may result in overuse of vaccine if the VIDAS MSG assay is used to determine immune status in screening programs such as pre-employment of hospital staff.

Optimizing the use of vision in manual aiming: the role of practice

The purpose of this study was to determine how subjects learn to adjust the characteristics of their manual aiming movements in order to make optimal use of the visual information and reduce movement error. Subjects practised aiming (120 trials) with visual information available for either 400 msec or 600 msec. Following acquisition, they were transferred to conditions in which visual information was available for either more or less time. Over acquisition, subjects appeared to reduce target-aiming error by moving to the target area more quickly in order to make greater use of vision when in the vicinity of the target. With practice, there was also a reduction in the number of modifications in the movement. After transfer, both performance and kinematic data indicated that the time for which visual information was available was a more important predictor of aiming error than the similarity between training and transfer conditions. These findings are not consistent with a strong "specificity of learning" position. They also suggest that, if some sort of general representation or motor programme develops with practice, that representation includes rules or procedures for the utilization of visual feedback to allow for the on-line adjustment of the goal-directed movement.

Use of the polymerase chain reaction for the detection of Chlamydia trachomatis from endocervical and urine specimens in an asymptomatic low-prevalence population of women

The Amplicor Chlamydia trachomatis test is a polymerase chain reaction (PCR)-based methodology used for the detection of a cryptic plasmid found in C. trachomatis. It was evaluated in comparison with cell culture and the Microtrak II Chlamydia enzyme immunoassay (EIA) for the detection of C. trachomatis in urogenital specimens from women. Endocervical swabs were collected from 993 women attending the women's unit at the Mount Sinai Hospital in Toronto. In addition, concomitant first void urine specimens were collected from 394 of these women for PCR testing only. As compared with culture of the endocervical specimens, PCR and EIA had a sensitivity, specificity, positive predictive value and negative predictive value of 84.6%, 99.2%, 57.9%, and 99.8% and 61.5%, 99.7%, 72.7%, and 99.5%, respectively. As compared with the secondary gold standard of a positive culture and/or a positive PCR using a primer to the major outer membrane protein the sensitivity, specificity, positive, and negative predictive values for culture were 72.2%, 100%, 100%, and 99.5%, respectively. For the Amplicor PCR and EIA the results were 88.9%, 99.7%, 84.2%, and 99.9% and 61.1%, 99.9%, 91.7%, and 99.6%, respectively. When the urine PCR was compared with the same standard, the test had a sensitivity of 91.7% and a specificity of 99.5%. Based on this study the Amplicor C. trachomatis test was found to be sensitive and specific for the detection of C. trachomatis in both endocervical and urine specimens.

Anomalous cerebral lateralization and Down syndrome

Contrary to Bryden, McManus, and Bulman-Fleming's claim, the dichotic listening and handedness literature indicate that persons with Down syndrome exhibit a unique pattern of cerebral specialization. This pattern creates difficulty for any model of laterality that proposes random specialization of function in the absence of a predisposition toward left hemisphere lateralization for language and motor control.

Effects of schizophrenia and prefrontal leukotomy on movement preparation and generation

The purpose of this study was to investigate the ability of leukotomized and unleukotomized schizophrenic patients to use advance information in the process of movement preparation. Subjects participated in an aiming task in which movements could be defined on the basis of hand used to perform the task, and distance travelled to the target. Subjects were provided with full, partial, or no prior information about the upcoming movement by either precueing hand, distance, both hand and distance, or by providing no precue. The leukotomized and unleukotomized schizophrenic patients were able to use this advance information to facilitate the speed of their responses in much the same way as did subjects in a normal control group. These results are discussed in terms of models of movement preparation, and the role of the frontal lobes in schizophrenia and movement planning.

The influence of intermittent vision on manual aiming

Two experiments were conducted to examine the influence of intermittent vision on right and left hand aiming. In Experiment 1, increased visual occlusion times led to a steady deterioration in performance that was most pronounced for high index of difficulty targets. Longer visual sample times only partially compensated for this effect (Experiment 2). It is suggested that a short-lived visual representation of the movement environment may in some cases provide a reasonable, although not perfect, substitute for direct visual pickup. In Experiment 2, there was some indication that the right hand system may be faster at using visual information than the left hand system.

Rapid detection of infectious mononucleosis-associated heterophile antibodies by a novel immunochromatographic assay and a latex agglutination test

A novel immunochromatographic assay, the CARDS O.S. MONO test (Pacific Biotech, San Diego, Calif.), and a latex agglutination test, the Infectious Mononucleosis Kit (Unipath Ltd., Hampshire, United Kingdom) were compared with the Paul-Bunnell-Davidsohn test. Of the 957 serum specimens studied, 78 were positive and 879 were negative by the Paul-Bunnell-Davidsohn test. After discrepancies were resolved by determining Epstein-Barr virus serology, the sensitivities of the CARDS O.S. MONO test and the Infectious Mononucleosis Kit were 91.0 and 96.2%, respectively, and both tests had a specificity and a positive predictive value of 100% and a negative predictive value and overall agreement of greater than 99%. The results show that both tests can accurately detect infectious mononucleosis-associated heterophile antibodies.

Asymmetries in the regulation of visually guided aiming

An experiment was conducted to examine the contribution of sensory information to asymmetries in manual aiming. Movements were performed in four vision conditions. In the full-vision condition (FV), subjects were afforded vision of both the hand and the target throughout the course of the movement. In the ambient-illumination-off condition (AO), the room lights were extinguished at movement initiation, preventing vision of the moving limb. In the target-off (TO) condition, the target was extinguished upon initiation of the movement. In a no-vision (NV) condition, ambient illumination was removed and the target was extinguished upon initiation of the response movement. Results indicated that accuracy was superior in the full-vision and target-off conditions and when movements were made by the right hand. Movements made by the right hand were also of shorter mean duration. The magnitudes of performance asymmetries were uninfluenced by vision condition. Analyses of movement kinematics revealed that movements made in conditions in which there was vision of the limb exhibited a greater number of discrete modifications of the movement trajectory. On an individual-trial basis, no relationship existed between accuracy and the occurrence of discrete modifications. These data suggest that although vision greatly enhances accuracy, discrete modifications subserved by vision reflect the imposition of nonfunctional zero-order control processes upon continuous higher-order control regimes.

Asymmetries in the spatial localization of transformed targets

This study was designed to examine the contribution of the right cerebral hemisphere in the spatial localization of visual targets for manual aiming. Visual targets were briefly presented to the right and left fields and subjects were required to point either to the target location, or a "mirror" image of the target location with their right or left index finger. Whereas reaction times were faster for left-hand pointing than for right-hand pointing, there was no differential effect of the mirror image transformation. This suggests that left-hand reaction time advantages are more related to right hemisphere involvement in the spatial parameterization of the movement than spatial localization of the target.

Comparative evaluation of seven commercial tests for detection of heterophile antibody in infectious mononucleosis

Detection of heterophile antibodies in infectious mononucleosis is the most rapid and cost-effective method for confirming the clinical diagnosis of the disease. This study compared seven commercial test kits (the Oxoid Infectious Mononucleosis Kit [Oxoid Ltd], Immunoscan Im-Latex [Baxter Travenol], Mono-Latex [Wampole Laboratories], Monospot and Im Screen Test [Ortho Diagnostics], Immunoscan Im-RBC Test [Baxter Travenol], and Infectious Mononucleosis Test [NCS Diagnostics]) to the Davidsohn differential test. All of the kits were shown to be acceptable for use, with specificities and sensitivities greater than 96.5% and 95.5%, respectively.