Students' expectations of learning key skills and knowledge

Students' expectations of the key skills and knowledge they acquire and how their perceptions of these change during the four year period of their speech and language therapy (SLT) degree programme are explored. This is important because students are central to the teaching and learning process so their expectations of learning have to be taken into account in order to best help them to achieve the required learning outcomes. Over 100 De Montfort University (DMU) SLT under-graduate students from the four years were surveyed by questionnaire. The research findings are discussed to examine the significance of differences between and within year cohorts. The outcomes of this research will provide a basis for recommendations for DMU and other universities' SLT programmes, and for the improvement of student learning guidance.

Mortality among males with hemophilia: relations with source of medical care. The Hemophilia Surveillance System Project Investigators

Although persons with hemophilia are known to be at increased risk of death, no studies have examined the source of medical care and other personal characteristics for associations with mortality. To determine death rates and to identify causes of death and predictors of mortality, we studied a cohort comprised of all hemophilic males identified by a six-state surveillance system. Data were obtained by medical record review of contacts with physicians, hemophilia treatment centers (HTCs), and other sources of care during 1993-1995 and from death certificates. Factors examined included age, race, state of residence, health insurance type, medical care source, hemophilia type/severity, presence of inhibitor, liver disease, HIV infection, and AIDS. A total of 2950 subjects were followed for an average of 2.6 years. Their median age was 22 years; 73% were white, 79% had hemophilia A, 42% had severe disease, and 67% had visited an HTC. During 7575 person years (PYs) of observation, 236 persons died-an age-adjusted mortality rate of 40.4 deaths/1000 PYs; 65% of deaths were HIV related. In addition to age, factors independently associated with increased risk of death (relative risk, P value) were the following: AIDS (33.5, <.001); HIV infection (4.7, <.001); liver disease (2.4, <.001); and Medicare/Medicaid insurance (1.4,. 01). Those persons who had received care in an HTC had a significantly decreased risk of death (0.6,.002). Although HIV infection and the presence of severe liver disease remain strong predictors of mortality, survival is significantly greater among hemophilics who receive medical care in HTCs. (Blood. 2000;96:437-442)

Exaggerating temporal differences enhances recognition of individuals from point light displays

Humans are very good at perceiving each other's movements. In this article, we investigate the role of time-based information in the recognition of individuals from point light biological motion sequences. We report an experiment in which we used an exaggeration technique that changes temporal properties while keeping spatial information constant; differences in the durations of motion segments are exaggerated relative to average values. Participants first learned to recognize six individuals on the basis of a simple, unexaggerated arm movement. Subsequently, they recognized positively exaggerated versions of those movements better than the originals. Absolute duration did not appear to be the critical cue. The results show that time-based cues are used for the recognition of movements and that exaggerating temporal differences improves performance. The results suggest that exaggeration may reflect general principles of how diagnostic information is encoded for recognition in different domains.

Traumatic brain injury: a view from the inside

Information about the outcomes after traumatic brain injury comes from observational studies and, increasingly, subjective sources. Narrative analysis provides an avenue to explore life after the trauma, and a perspective that may illuminate critical aspects of the relationship between the health professional and health consumer. Language use by health professionals in their interactions with health consumers may profoundly bias expectations and outcomes. Terms such as 'recovery', for example, may be inappropriate, as severe traumatic brain injury may not be an injury that one is able to 'recover' from. If the brain is seen as the basis of the personality and is altered by the trauma, then, philosophically, it is difficult to argue that the person is the same as before. Concepts of rehabilitation after severe traumatic brain injury should, therefore, take into account the expectation of the health consumer in shaping the outcomes and the possibility that new and adaptive patterns of behaviour need to be developed rather than focusing on returning to the pre-injured person. This introduces the notion of rehabilitation as assisting the injured person to re-orientate or rebuild their life using a new set of 'maps' with which to navigate through life. The paradigm of 'new maps' is positive, challenging, and honest as far as expectations are concerned, and encompasses the idea of actively exploring new and unknown territory.

Electrophysiological correlates of direct versus indirect semantic priming in normal volunteers

The N400 component of event related potentials (ERP) was studied in 27 right-handed healthy subjects in a speeded lexical decision task. The semantic distance between primes (always words) and targets (50% words, 50% non-words) was systematically varied. Prime-target relations included directly related words (hen-egg), indirectly related words (lemon-sweet), and non-related words (sofa-wing). ERPs were recorded from 20 scalp electrodes positioned according to the international 10-20 system. The N400 reflected semantic distance with the most negative and latest N400 peak in the non-related condition, the least negative and earliest N400 peak in the direct condition and the peak in the indirect condition in-between. Hence, N400 priming effect in the indirect condition was obtained in the absence of strong sentential constraints and even though the mediating word was physically not present.

The relation between asymmetry and amplitude of the P300 field in schizophrenia

OBJECTIVES

A general reduction of auditory P300 amplitude is one of the most consistently replicated observations in schizophrenic patients. However, a left hemisphere amplitude reduction is discussed controversely.

METHODS

Encouraged by this controversy we analysed P300 data of 53 controls and 60 patients of the schizophrenia spectrum (ICD-10: F20, F23, F25).

RESULTS

Our main result was the finding of the correlation between general amplitude and hemispheric asymmetry in the patient group: low general amplitudes were assigned to a left hemispheric amplitude reduction, high amplitudes to a right hemispheric reduction. Based on this result, we grouped all subjects according to their hemispheric asymmetry pattern. The control group and the group of schizoaffective patients (F25) with a left hemispheric amplitude reduction showed the inverse asymmetry pattern of P300 amplitude compared to subjects with a right hemispheric amplitude reduction. In contrast, the schizophrenic patients (F20) showed only a difference in P300 amplitudes measured at electrode sites of the left hemisphere. Additionally, we could show, that the amount of the general amplitude reduction in patients was different between the diagnostic groups.

CONCLUSIONS

We conclude that a left hemispheric amplitude reduction is not a general feature of schizophrenia but it seems to be pathological when combined with a general amplitude reduction.

Genetic influence on auditory information processing in schizophrenia: P300 in monozygotic twins

BACKGROUND

It is widely accepted that schizophrenia is to some extent genetically determined. Abnormalities of the P300 component are one of the most robust biological findings in schizophrenia. They outlast clinical impairment and are present also in relatives of schizophrenic patients. In the present study on schizophrenic twins, the heritability of auditory P300 abnormalities and the influence of task difficulty on heritability was examined.

METHODS

Twenty-two monozygotic twin pairs were included into this study (eight pairs discordant, five pairs concordant for schizophrenia or schizoaffective psychosis according to ICD-10 criteria, and nine control pairs). Two different versions of the auditory oddball paradigm were used to control for deficient stimulus perception.

RESULTS

Compared to healthy controls, P300 amplitudes were significantly smaller in affected twins as well as in the non-affected co-twins of the discordant pairs.

CONCLUSIONS

Our results suggest that P300 amplitude reduction is a genetically transmitted vulnerability marker for schizophrenia. Because the findings were independent of the difficulty of the task and could be demonstrated even when pitch disparity was adjusted to the subjects' ability to discriminate tones, the findings can not be related to the genetic influence on higher information processing.

Comparison of large restriction fragments of Mycobacterium avium isolates recovered from AIDS and non-AIDS patients with those of isolates from potable water

We examined potable water in Los Angeles, California, as a possible source of infection in AIDS and non-AIDS patients. Nontuberculous mycobacteria were recovered from 12 (92%) of 13 reservoirs, 45 (82%) of 55 homes, 31 (100%) of 31 commercial buildings, and 15 (100%) of 15 hospitals. Large-restriction-fragment (LRF) pattern analyses were done with AseI. The LRF patterns of Mycobacterium avium isolates recovered from potable water in three homes, two commercial buildings, one reservoir, and eight hospitals had varying degrees of relatedness to 19 clinical isolates recovered from 17 patients. The high number of M. avium isolates recovered from hospital water and their close relationship with clinical isolates suggests the potential threat of nosocomial spread. This study supports the possibility that potable water is a source for the acquisition of M. avium infections.

Phase II evaluation of 5-fluourouracil plus folinic acid and alpha 2b-interferon in metastatic colorectal cancer

Biochemical modulation of 5-fluorouracil (5-FU) by folinic acid (FA) increases the response rate in patients with metastatic colorectal cancer compared to 5-FU alone. Phase II trials also demonstrated increased efficacy when interferon was added to 5-FU. In two consecutive trials, 76 patients were treated on days 1-5 with FA 200 mg/m2 plus interferon 5 x 10(6) U/m2 and 5-FU 350 mg/m2 as intravenous bolus injection (n = 33, regimen A) or 5-FU 500 mg/m2 as 2-hour infusion (n = 43, regimen B), repeated every 3 weeks with individual 5-FU dose escalation in steps of 50 (regimen A) or 100 mg/m2 (regimen B). In regimen A 5-FU dose reduction to 300 mg/m2 due to toxicity was necessary in 49% of the patients; in regimen B a 5-FU dose of 600 mg/m2 or above was tolerated by 70% of the patients. Dose-limiting toxicity was severe mucositis and/or diarrhea. Objective responses were observed in 5 of 33 patients (15%) in regimen A (3-28%, 95% confidence interval) and 7 of 41 patients (17%) in regimen B (5-29%, 95% confidence interval). Median time to progression was 4.7 and 4.8 months, and median survival 9.9 and 11.4 months for regimens A and B, respectively. Prolonged 5-FU administration over 2 h allows the administration of a higher 5-FU dose compared to bolus injection with no apparent improvement in antineoplastic efficacy. The addition of interferon to the combination of 5-FU plus FA in this dose and schedule does not seem to improve the response rate but appears to increase treatment toxicity.

Left lateralized P300 amplitude deficit in schizophrenic patients depends on pitch disparity

The general reduction of P300 amplitude in response to auditory oddball stimuli is one of the most consistently replicated biological observations in schizophrenic patients. Several groups have reported a P300 asymmetry in schizophrenic patients, others have not been able to replicate this finding. In order to clarify this issue, we examined the effect of stimulus discriminability on P300 amplitude distribution in schizophrenic patients and in age-matched normal control subjects, using two different auditory oddball paradigms. The detection of the target tone was either simple or difficult, due to manipulation of pitch disparity. The P300 amplitude was comparatively smaller in the schizophrenic patient group compared to the healthy controls and in the difficult task compared to the simple. The schizophrenic patients showed a specific P300 amplitude reduction over left temporal electrode sites when the simple paradigm was used. The difficult paradigm did not elicit asymmetrical P300 amplitudes in schizophrenic patients.

Information and viewpoint dependence in face recognition

How we recognize faces despite rotations in depth is of great interest to psychologists, computer scientists and neurophysiologists because of the accuracy of human performance despite the intrinsic difficulty of the task. Three experiments are reported here which used three-dimensional facial surface representations to investigate the effects of rotations in depth on a face recognition task. Experiment 1, using "shape only" representations, showed that all the views used (full-face, three-quarter and profile) were equally well recognized when all had been learned. Performance was better when the same views were presented in an animated sequence rather than at random, suggesting that structure-from-motion provides useful information for recognition. When stimuli were presented inverted, performance was worse and there were differences in the recognizability of views, demonstrating that the familiarity of upright faces affects generalization across views. Experiments 2 and 3 investigated generalization from single views and found performance to be dependent on learned view. In both experiments, generalization from learned full-face fell off with increasing angle of rotation. With shape only stimuli, three-quarter views generalized well to each other, even when inverted but for profiles generalization was equally bad to all unlearned views. This difference may be explained because of the particular relationship of the profile to the axis of symmetry. In Experiment 3, addition of information about superficial properties including color and texture facilitated performance, but patterns of generalization remained substantially the same, emphasizing the importance of underlying shape information. However, generalization from the three-quarter view became viewpoint invariant and there was some evidence for better generalization between profiles. The results are interpreted as showing that three-dimensional shape information is fundamental for recognition across rotations in depth although superficial information may also be used to reduce viewpoint dependence.

Effects of lighting on the perception of facial surfaces

A series of experiments is reported that investigated the effects of variations in lighting and viewpoint on the recognition and matching of facial surfaces. In matching tasks, changing lighting reduced performance, as did changing view, but changing both did not further reduce performance. There were also differences between top and bottom lighting. Recognizing familiar surfaces and matching across changes in viewpoint were more accurate when lighting was from above than when it was from below the heads, and matching between different directions of top lighting was more accurate than between different directions of bottom lighting. Top lighting also benefited matching between views of unfamiliar objects (amoebae), though this benefit was not found for inverted faces. The results are difficult to explain if edge- or image-based representations mediate face processing and seem more consistent with an account in which lighting from above helps the derivation of 3-dimensional shape.

Effects of lighting on the perception of facial surfaces

A series of experiments is reported that investigated the effects of variations in lighting and viewpoint on the recognition and matching of facial surfaces. In matching tasks, changing lighting reduced performance, as did changing view, but changing both did not further reduce performance. There were also differences between top and bottom lighting. Recognizing familiar surfaces and matching across changes in viewpoint were more accurate when lighting was from above than when it was from below the heads, and matching between different directions of top lighting was more accurate than between different directions of bottom lighting. Top lighting also benefited matching between views of unfamiliar objects (amoebae), though this benefit was not found for inverted faces. The results are difficult to explain if edge- or image-based representations mediate face processing and seem more consistent with an account in which lighting from above helps the derivation of 3-dimensional shape.

Perceiving the sex and race of faces: the role of shape and colour

Theories of object recognition have emphasized the information conveyed by shape information, whereas theories of face recognition have emphasized properties of superficial features. In the experiments reported here we used novel technology to investigate the relative contributions of shape and superficial colour information to simple categorization decisions about the sex and 'race' of faces. The results show that both shape and colour provide useful information for these decisions; shape information was particularly useful for race decisions while colour dominated sex decisions. When both sources of information were combined, the dominant source depended on viewpoint, with angled views emphasizing the contribution of shape and the full-face view colour. The results are discussed within the context of theories of face recognition and their implications for telecommunication applications are considered.

Characterization of B-cell lines established from two X-linked severe combined immunodeficiency patients: interleukin-15 binds to the B cells but is not internalized efficiently

X-linked severe combined immunodeficiency (XSCID) is characterized by absent or profoundly reduced numbers of T cells and normal numbers of B cells in the circulation. Affected patients have mutations of the interleukin-2 (IL-2) receptor gamma chain gene. Using Epstein-Barr virus-transformed B-lymphoblastoid cell lines (B-LCLs) established from two unrelated XSCID patients, we could show that neither expressed the IL-2 receptor gamma chain on the cell surface. A novel cytokine IL-15, which has biologic activities similar to those of IL-2, could bind to the XSCID B-LCLs in the absence of the gamma chain, although both the beta and gamma chains of the human IL-2 receptor were previously shown to be required for IL-15 binding by transfected COS cells. Furthermore, a significant reduction and delay of IL-15 internalization by B lymphoblasts from XSCID patients was observed when compared with that of normal control B-LCLs. These results show the existence of a novel IL-15-specific receptor component that contributes to IL-15 binding but is insufficient for IL-15 internalization in the absence of the IL-2 receptor gamma chain.

Placental transfer and neonatal effects of epidural sufentanil and fentanyl administered with bupivacaine during labor

BACKGROUND

This randomized double-blind investigation was designed to study the placental transfer and neonatal effects of epidural sufentanil and fentanyl infused with bupivacaine for labor analgesia.

METHODS

Healthy parturient women (n = 36) received epidural bupivacaine alone (group B) or with fentanyl (group B-F) or sufentanil (group B-S). Group B received a 12-ml bolus of 0.25% bupivacaine followed by a 10 ml/h infusion of 0.125% bupivacaine. Groups B-F and B-S received a 12-ml bolus of 0.125% bupivacaine with 75 micrograms fentanyl or 15 micrograms sufentanil, respectively, followed by 10 ml/h of 0.125% bupivacaine with fentanyl 1.5 micrograms/ml or sufentanil 0.25 micrograms/ml. Maternal venous (MV) and umbilical arterial (UA) and umbilical venous (UV) bupivacaine and opioid plasma concentrations were determined. Neonatal assessment included Apgar scores, umbilical cord blood gas analyses, and neurobehavioral testing at delivery and at 2 and 24 h of life using the Neurologic and Adaptive Capacity Score (NACS).

RESULTS

The mean total dose of fentanyl was 136.6 +/- 13.1 micrograms (SEM), and of sufentanil, 23.8 +/- 1.8 micrograms. Although administered in a ratio of 5.7:1, fentanyl and sufentanil MV plasma concentrations were in the ratio of 27:1. UV/MV ratios were 0.37 for fentanyl and 0.81 for sufentanil. Fentanyl was detected in most UA samples, whereas sufentanil was present in only one sample. Neonatal condition was good and generally similar in all groups, with the exception of a lower NACS at 24 h in group B-F.

CONCLUSIONS

Although the degree of placental transfer of sufentanil appeared greater than that of fentanyl, lower MV sufentanil concentrations resulted in less fetal exposure to sufentanil. The lower NACS at 24 h in group B-F may reflect the continued presence of fentanyl in the neonate.

The random inactivation of the X chromosome carrying the defective gene responsible for X-linked hyper IgM syndrome (X-HIM) in female carriers of HIGM1

The molecular origin of X-linked hyper IgM syndrome has recently been identified as a defect in the ligand of CD40, gp39, a protein expressed on the surface of activated T cells. The availability of detailed pedigrees for three families with affected males allowed assessment of the random or nonrandom nature of the inactivation of the defective X chromosome as well as a determination of the origin of the mutation. X chromosome inactivation was studied because of the relevance to the ability to detect carriers of HIGM1 and the potential for phenotypic effect in the carriers. Using immunostaining, PCR, and DNA sequencing, we found that the defective gene for gp39 is not selectively inactivated. Even in the presence of extremely skewed inactivation, normal levels of serum Ig were found. In carriers in which the defective gene is predominantly expressed, staining alone revealed the carrier status reliably while cloning and sequencing of the cDNA was necessary when the normal gene was predominantly expressed. Unlike some other X-linked defects where extreme Lyonization may lead to disease, a small population of cells expressing the wild-type gp39 is sufficient to maintain normal humoral immunity and prevent the clinical symptoms of X-HIM.

Independent effects of lighting, orientation, and stereopsis on the hollow-face illusion

Three experiments were conducted to investigate factors contributing to the 'hollow face' illusion. A novel method was employed in which the distance from the mask at which the illusion became apparent or disappeared, when retreating or approaching, respectively, was taken as a measure of the strength of the illusion. In all the experiments an effect of direction of observer's movement was found, demonstrating the stability of the initial percept. Upright orientations were compared with inverted ones to investigate if the illusion reflects a bias towards a familiar percept. The direction of lighting was also varied. Independent main effects of orientation and lighting were found to be consistent with preferences both for upright faces and for top lighting. However, inverted faces also produced the illusion to some extent, suggesting a general preference for convexity. The role of stereopsis in resolving the illusion was tested by comparing monocular with binocular viewing conditions. Monocular viewing conditions gave rise to shorter distances, suggesting that the retinal disparities available with binocular viewing are important in disambiguating the illusion at small distances. The results are interpreted within the framework of a 2 1/2-dimensional sketch derived from independent modular processing of visual information.

Behavioural mechanisms in AIDS patients under stress

Clinical observation at the Kenyatta National Hospital showed unusually rapid deterioration of patients testing seropositive to HIV infection and being moved to a side room for nursing. This pilot study tested the hypothesis that deterioration was at least partly, mediated by B-endorphins and other endogeneous opioids. The study design was a prospective and comparative study looking at 6 HIV seropositive and 10 control (HIV seronegative) patients matched for sex, age, and clinical status at time of study. The laboratory measures compaired were baseline, and daily serum B-endorphin and ACTH. A significant variation is noted between the two groups. The significance of this study is discussed.