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PubMed1997

High-yield platelet concentrates attainable by continuous quality improvement reduce platelet transfusion cost and donor exposure.

BACKGROUND: Donor exposure risk and cost in platelet transfusion practice can be limited by increasing the recovery of platelets from donor units. STUDY DESIGN AND METHODS: This study presents results of continuous quality improvement efforts in platelet production and compares the in vivo therapeutic efficacy of currently produced platelet concentrates (PCs) with that of apheresis platelets. Production quality improvement measures included optimization of instrument performance (rotor speed trials), process (massaging whole-blood units, using cup liners, limiting spin-expression time, and refining plasma expression technique), and staff (intensive training with observation and ongoing quality control data feedback). Corrected count increments and increments per kg were calculated for transfusions of 4 pooled PCs and apheresis platelets over a 30-day period. RESULTS: The mean number of platelets per PC increased from 5.5 x 10(10) in 1975 to 9.69 x 10(10) in 1994. The mean platelet dose was 3.78 x 10(11) for 4 PCs and 4.17 x 10(11) for apheresis platelets. A total of 34 pooled PCs and 17 apheresis platelets was transfused to 21 patients. The mean increment, the increment per kg, and the corrected count increment were, respectively, 31 x 10(3) per microL, 4.8 x 10(2) per microL, and 14,700 for 4 PCs and 35.4 x 10(3) per microL, 5.4 x 10(2) per microL, and 14,700 for apheresis platelets. Differences were not significant. CONCLUSION: Therapeutic efficacy comparable to that of apheresis platelets can be obtained with 4 high-yield PCs.

Blood Donors↗

PubMedDate not supplied

Teat disorders predispose ewes to clinical mastitis after challenge with Mannheimia haemolytica.

In order to study the effects of sheep teat disorders on the protection of the mammary gland, we used a Mannheimia haemolytica isolate, which did not cause clinical mastitis when deposited into intact teats. In the first experiment, this was deposited into the duct of teats with orf (Group A, n=5) or papilloma (Group B, n=3). In the second, teats were chapped and then, the organism was deposited into the duct (Group C, n=7) or on the skin (Group D, n=4). Ewes with healthy teats were controls (Group E, deposition into duct, n=5; Group F, deposition on skin, n=2). The ewes in Groups A, B or C developed clinical mastitis 5 h later, whilst the ewes in Group D developed it 2 d later; no control ewe developed clinical mastitis. In ewes with teat lesions, the organism was isolated from secretion samples and the California Mastitis Test became positive 5 h after challenge; neutrophils and lymphocytes were seen in Giemsa-stained secretion films from Group A or B ewes, whilst macrophages, neutrophils and lymphocytes in films from Group C or D ewes; neutrophils were predominating in films from Group E or F ewes. Inside the teats of Group A, B, C or D ewes, folds, hyperaemia and mucosal thickness were seen; histologically, subepithelial leucocytic infiltration was seen. In Group A or B ewes, no evidence of lymphoid tissue at the teat duct-cistern border was found. In Group C or D ewes, intense erosion and ulceration of the teat skin and conspicuous lymphoid tissue at the teat duct-cistern border, were evident; lesions characteristic of haemorrhagic mastitis were in the mammary parenchyma. In control ewes, subepithelial leucocytic infiltration in the teat duct and lymphoid tissue as above, were evident. We postulate that teat lesions can be predisposing factor to mastitis, by adversely affecting defences and speeding the process of infection and making it more severe.

Animals↗

PubMed2005

Hyphenated NMR methods in natural products research, part 1: direct hyphenation.

This review describes the current status of the development of techniques combining liquid chromatography and nuclear magnetic resonance and their use in the context of natural products. HPLC-NMR methods have a rapidly growing impact on natural products research by enabling structure determination of natural products directly from small amounts of extracts, i. e., prior to the investment in an often lengthy and laborious preparative-scale isolation process. This speeds up extract dereplication and helps to avoid re-isolation of already known extract constituents. Direct HPLC-NMR hyphenation techniques, defined as methods in which NMR spectra are recorded using the HPLC eluate, are described. The recently developed indirect HPLC-NMR method employing an automated solid-phase extraction interface between HPLC and NMR, which replaces the chromatographic solvent with a different solvent for NMR data acquisition, is described in the second part of this review.

Chromatography, High Pressure Liquid↗

PubMed2003

The building blocks of cognition.

This article provides an overview of some innovative ways of examining infant cognition, highlighting several procedures that are likely to prove useful for assessing the effects of interventions in the first year of life. The procedures singled out assess three aspects of cognition in infancy: visual recognition memory, attention, and speed of processing. Assessments of each, while primarily experimental in nature, show strong developmental change over the first year, as well as modest stability, discriminant validity, and predictive validity. The emerging evidence suggests that these three aspects of infant cognition are among the most basic building blocks of mature cognition.

Attention↗

PubMed1990

Reaction time measures of feature saliency in schematic faces.

Two separate paradigms utilizing measurements of reaction time were employed to study facial feature saliency in schematic line drawn faces. In the first paradigm the speed of response to the omission of different facial components was measured, and in the second, the speed of response to feature substitution was measured. In both paradigms the facial features were presented in a random temporal sequence in order to minimise preferential scanning strategies. The two separate paradigms reflected the feature hierarchy most commonly found in the literature, ie the outline and eyes are more salient than the nose and mouth in terms of both speed of processing and error rate. In a third study the feature substitution paradigm was used to investigate the effects of feature saliency on the perception of emotional faces. The results suggest a change in the eyes/mouth hierarchy so that the mouth becomes the most salient feature in the surprised, happy, and sad target faces. This reverse in hierarchy, however, was not evident with the angry target face. These results are discussed in terms of changes in the focus of 'attention' and/or changes in 'processing efficiency'.

Adult↗

PubMed2006

Sometimes area counts more than number.

Using an interference paradigm, we show across three experiments that adults' order judgments of numbers, sizes, or combined area of dots in pairs of arrays occur spontaneously and automatically, but at different speeds and levels of accuracy. Experiment 1 used circles whose sizes varied between but not within arrays. Variation in circle size interfered with judgments of which array had more circles. Experiment 2 used displays in which circle size varied within and between arrays. Between-array differences in the amount of "circle stuff" (area occupied by circles) interfered with judgments of number. Experiment 3 examined whether variation in number also interferes with judgments of area. Interference between discrete and continuous stimulus dimensions occurred in both directions, although it was stronger from the continuous to the discrete than vice versa. These results bear on interpretations of studies with infants and preschoolers wherein subjects respond on the basis of continuous quantity rather than discrete quantity. In light of our results with adults, these findings do not license the conclusion that young children cannot represent discrete quantity. Absent data on attentional hierarchies and speed of processing, it is premature to conclude that infant and child quantity processes are fundamentally different from that of adults.

Adult↗

PubMed1996

Aberdeen polygons: computer displays of physiological profiles for intensive care.

The clinician in an intensive therapy unit is presented regularly with a range of information about the current physiological state of the patients under care. This information typically comes from a variety of sources and in a variety of formats. A more integrated form of display incorporating several physiological parameters may be helpful therefore. Three experiments are reported that explored the potential use of analogue, polygon diagrams to display physiological data from patients undergoing intensive therapy. Experiment 1 demonstrated that information can be extracted readily from such diagrams comprising 8- or 10-sided polygons, but with an advantage for simpler polygons and for information displayed at the top of the diagram. Experiment 2 showed that colour coding removed these biases for simpler polygons and the top of the diagram, together with speeding the processing time. Experiment 3 used polygons displaying patterns of physiological data that were consistent with typical conditions observed in the intensive care unit. It was found that physicians can readily learn to recognize these patterns and to diagnose both the nature and severity of the patient's physiological state. These polygon diagrams appear to have some considerable potential for use in providing on-line summary information of a patient's physiological state.

Adult↗

PubMed1993

Age differences in memory-span errors: speed or inhibitory mechanisms?

This study investigated age differences in errors on the digit-span task. Protocols of 119 men and women, aged 18-99 years, were scored for the occurrence of three types of errors derived from the speed-of-processing and inhibition-deficit frameworks: omission errors, intrusion errors, and transposition errors. The types of errors made on the digit-span task varied with span size. At larger span sizes, participants were more likely to omit digits or introduce nonstimulus digits than to transpose those in storage. No age differences in intrusion errors were found, however, old-old women (75+ years) were significantly more likely than young (18-25 years) and old (60-70 years) adults of either sex to exhibit transposition errors. Consequently, old-old women were significantly less likely to exhibit omission errors. The results indicate that the digit-span task may involve two parallel processes: digit storage/recall and serial/position storage-recall. Age differences in the serial-processing component, rather than in the digit storage/recall component, may be age sensitive. These results are discussed within an inhibition-deficit framework of cognitive aging.

Adolescent↗

PubMed1990

Assessing MMPI constructs through the measurement of response latencies.

Responses to the Minnesota Multiphasic Personality Inventory (MMPI) were assessed with respect to their relevance to schema theory. The relation between scores on self-reported personality dimensions and the speed of processing test items associated with each dimension was examined. With previously derived factor analytic content scales, negative correlations were obtained between scale scores and mean latencies for endorsing relevant items, and positive correlations were found between scale scores and mean latencies for rejecting relevant items. A similar analysis completed on the traditional clinical scales revealed no such pattern. Results were interpreted as supporting the conceptualization of item responding as a content-based, schema-relevant process.

Adult↗

PubMed1993

A meta-analysis of the relative sensitivity of neuropsychological screening tests.

The National Institute of Mental Health recently formed a committee of experts which published a proposal for a lengthy neuropsychological test battery judged most apt to detect diffuse brain damage while covering a wide range of cognitive abilities. The purposes of the present study were (1) to assemble empirical evidence of the existence of statistically significantly sensitive screening tests across an equivalently wide range of functional domains, and (2) to present this evidence systematically, in such a manner as to help clinicians select subsets of screening tests manifesting greatest sensitivity to diffuse brain damage. It was found that in certain functional domains (speed of processing, problem solving, executive functions), marked differences in sensitivity occurred. Brief tests just as sensitive as time-consuming tests were also identified. The reader is cautioned about possible extraneous sources of the differences obtained (test and group selection bias, test reliability, test difficulty, procedural effects, Type I error). Nevertheless, it was concluded that a brief highly sensitive and functionally wide-ranging neuropsychological test battery for screening cases of putative diffuse brain dysfunction can be assembled.

Attention↗

PubMed2002

The neurobehavioural consequences of St. Louis encephalitis infection.

BACKGROUND: St. Louis encephalitis (SLE) is a relatively common cause of neurological illness, yet little is known about its cognitive and psychosocial consequences. PURPOSE: To describe the cognitive, emotional, psychophysiological, and psychosocial consequences of SLE infection. METHOD: A comprehensive neuropsychological and psychophysiological evaluation of a high functioning woman 6 weeks and 1 year after acute SLE infection is presented. The focus and course of rehabilitation is also examined. RESULTS: The primary cognitive consequences of SLE infection involved attention, working memory, speed of processing, and cognitive efficiency. Depression was also observed. Psychometric testing suggested that these deficits largely resolved after 1 year. CONCLUSIONS: SLE produces neurocognitive deficits which are reflected in both psychometric and psychophysiologic measures and functional status. Psychometric and vocational improvement were observed over 1 year. However, the normal vocational return came at a significant psychosocial cost. This case emphasizes the importance of a comprehensive neuropsychological evaluation and illustrates the importance of an integrated rehabilitation programme.

Adult↗

PubMed2006

Recovery from sports concussion in high school and collegiate athletes.

INTRODUCTION: Neuropsychological testing is a valuable tool in concussion diagnosis and management. ImPACT, a computerized neuropsychological testing program, consists of eight cognitive tasks and a 21-item symptom inventory. METHOD: ImPACT was used to examine the cognitive performance of 104 concussed athletes at baseline, 2, 7 and 14 days post-injury. Dependent measures included composite scores from the ImPACT computerized test battery, as well as a total symptom score from the Post-Concussion Symptom Scale. RESULTS: Differences between baseline and day 2 post-injury scores were observed for all ImPACT composites (Verbal memory-VERM, visual memory-VISM, processing speed-PROC and reaction time-RT) as well as in total symptom score (SX). At day 7, concussed athletes continued to perform significantly poorer on VERM, VISM, RT and SX. At day 14, only VERM scores were significantly different from baseline. CONCLUSIONS: Cognitive performance deficits in concussed athletes may persist to 7 and even to 14 days in some cases. In addition to symptom status, the athlete's post-concussion cognitive functioning should be considered when making return-to-play decisions.

Adolescent↗

PubMed2006

Motor deficits and recovery during the first year following mild closed head injury.

OBJECTIVE: This study examined motor impairments over 1 year following mild closed head injury (CHI). It is the first study to serially assess long-term oculomotor and upper-limb visuomotor function following mild head trauma. METHODS: Thirty-seven patients with mild CHI and 37 matched controls were compared at 1 week, 3 months and 6 months and 31 available pairs at 12 months post-injury on measures of saccades, oculomotor smooth pursuit, upper-limb visuomotor function and neuropsychological performance. Symptomatic recovery was sampled using the Rivermead Postconcussion Symptoms Questionnaire. RESULTS: At 1 week, the group with CHI reported high levels of post-concussional symptoms and exhibited prolonged saccade latencies, increased directional errors, decreased saccade accuracy and impaired fast sinusoidal smooth pursuit concomitant with increased arm movement reaction time, decreased arm movement speed and decreased motor accuracy on upper-limb visuomotor tracking tasks. Neuropsychological testing identified deficits only in verbal learning and speed of processing while attention, short-term/working memory and general cognitive performance were preserved. At 3 and 6 months, the group with CHI continued to show deficits on several oculomotor and upper-limb visuomotor measures in combination with some deficits on verbal learning and improved, yet abnormal, levels of post-concussional symptoms. At 12 months, the group with CHI had no cognitive impairment but residual deficits in eye and arm motor function and continued to show elevated levels of post-concussional symptoms. CONCLUSIONS: The findings indicate that multiple motor systems are measurably impaired up to 12 months following mild CHI and that instrumented motor assessment may provide sensitive and objective markers of cerebral dysfunction during recovery from mild head trauma independent of neuropsychological assessment and patient self-report.

Adolescent↗

PubMed2004

Parallel programming of exogenous and endogenous components in the antisaccade task.

In the antisaccade task subjects are required to suppress the reflexive tendency to look at a peripherally presented stimulus and to perform a saccade in the opposite direction instead. The present studies aimed at investigating the inhibitory mechanisms responsible for successful performance in this task, testing a hypothesis of parallel programming of exogenous and endogenous components: A reflexive saccade to the stimulus is automatically programmed and competes with the concurrently established voluntary programme to look in the opposite direction. The experiments followed the logic of selectively manipulating the speed of processing of these components and testing the prediction that a selective slowing of the exogenous component should result in a reduced error rate in this task, while a selective slowing of the endogenous component should have the opposite effect. The results provide evidence for the hypothesis of parallel programming and are discussed in the context of alternative accounts of antisaccade performance.

Attention↗

PubMedDate not supplied

Effects of aging on the generation of mental images.

Image generation is one component of mental imagery, and consists in the activation of stored visual information in long-term memory to sequentially create a temporary pattern on a visuospatial short-term memory display. Little is known about the fate of image generation over the human life span. In the present study, 165 healthy participants aged 18 to 80 years were enrolled for an image generation task to image an uppercase letter in response to its lowercase version displayed as the cue, and to decide if a displayed probe would be near to or on the image. Uppercase letters were simple versus complex, and the probe appeared in a region of the uppercase letter that is generated early versus late. Comparative analyses (ANOVAs) on accuracy and correct latency confirmed the sequential nature of image generation, and showed a detrimental and linear effect of aging only on the activation subprocess. Structural analyses (LISREL) revealed, however, that these effects of age were entirely mediated by inhibition mechanisms, speed of processing, and working memory.

Adolescent↗

PubMedDate not supplied

A growth curve model of learning acquisition among cognitively normal older adults.

The objective of this study was to model recall and learning on the Auditory Verbal Learning Test using latent growth curve techniques. Participants were older adults recruited for the ACTIVE cognitive intervention pilot. A series of nested models revealed that an approximately logarithmic growth curve model provided optimal fit to the data. Although recall and learning factors were statistically uncorrelated, a fitted multivariate model suggested that initial recall was significantly associated with demographic characteristics but unrelated to health factors and cognitive abilities. Individual differences in learning were related to race/ethnicity, speed of processing, verbal knowledge, and global cognitive function level. These results suggest that failing to recognize initial recall and learning as distinct constructs clouds the interpretation of supraspan memory tasks.

Aged↗

PubMed2004

Childhood-onset multiple sclerosis and mood disorders: a case study.

Multiple Sclerosis (MS) is rare in children. Little research exists regarding emotional and behavioral disorders in childhood-onset MS, despite the occurrence of such problems in adults with MS. This paper describes the cognitive and behavioral characteristics of a boy diagnosed with MS at age 9 and mood disorder at age 10. He displayed no cognitive or behavioral problems prior to the onset of physical symptoms of MS. Three years after diagnosis, this child showed persistent problems with speed of processing, visual-motor skills, and parent and teacher-reported executive functioning. In addition, he had difficulties with emotional lability, behavioral disinhibition, depression, and social interaction. As with adults, children with MS may be at increased risk for mood disorder compared to their peers. Mood disorders in children with MS are likely to be multiply determined, although the specific causal mechanisms are unknown.

Age of Onset↗

PubMed1994

Irradiation with He--Ne laser can influence the cytotoxic response of HeLa cells to ionizing radiation.

A monolayer of HeLa cells in plateau-phase of growth was exposed to He--Ne laser radiation (632.8 nm, 100 J/m2) either 5, 60 or 180 min before gamma-irradiation (0.2-10 Gy, 6.75 Gy/min). In the case of a 5 min interval between the two types of irradiations the survival curve was practically identical to the survival curve of the cells after gamma-irradiation only. In the case of He--Ne laser exposure 60 min before gamma-irradiation with doses > 5 Gy, a fraction of more resistant cells was revealed: their Do was twice as high as the Do of the main population (3.6 and 1.7 Gy, respectively). A preexposure of cells to He--Ne laser (100 J/m2) 60 or 180 min before gamma-irradiation (5 Gy) also changed the shape of the growth curves as compared with gamma-irradiated cells (stimulation in exponential phase of growth). It is proposed that the preexposure of cells to He--Ne laser radiation activates, in a subpopulation of cells, processes which speed up the repair of gamma-radiation damage. The possibility that the described phenomenon is an adaptive response of cells is discussed.

Cell Division↗