Extended-release tacrolimus dosing and outcomes in pediatric and young adult transplant recipients - A single-center experience

BACKGROUND

Published data on LCP-tacrolimus (LCPT) in the pediatric population are limited.

METHODS

This single-center, retrospective, observational study describes LCPT doses needed to reach therapeutic ranges in pediatric and young adult kidney and liver transplant recipients in both de novo usage and conversion from immediate-release tacrolimus (IR-Tac). Adverse outcomes up to 12 months after LCPT initiation were also evaluated.

RESULTS

Forty-one transplant recipients (30 kidney, 11 liver) were included. The median initial doses of LCPT were 0.034 mg/kg (IQR 0.019) de novo and 0.09 mg/kg (IQR = 0.076) converted. The median doses at first therapeutic level were 0.086 mg/kg (IQR 0.028) de novo and 0.1 mg/kg (IQR 0.066) converted. The median LCPT:IR-Tac conversion ratio initially was 0.7 and 0.75 at therapeutic levels. The rate of AKI per 100 days of exposure to IR-Tac was 0.546 and 0.439 on LCPT. The percentage of patients with rejection was not different before and after conversion (clinical rejection 8.6% [n = 3] vs 11.4% [n = 4], p = .6; biopsy-proven rejection 2.9% [n = 1] vs 11.4% [n = 4], p = .11). One patient had graft loss unrelated to rejection, and the graft was explanted.

CONCLUSION

In this study, pediatric and young adult abdominal transplant recipients had therapeutic tacrolimus levels at LCPT doses below the adult-labeled dose; the conversion ratio from IR-Tac to LCPT at therapeutic level was similar. There were no identified safety concerns in de novo or converted LCPT use in pediatric and young adult patients.

Improving access to affordable quality-assured inhaled medicines in low- and middle-income countries

BACKGROUND: Access to affordable inhaled medicines for chronic respiratory diseases (CRDs) is severely limited in low- and middle-income countries (LMICs), causing avoidable morbidity and mortality. The International Union Against Tuberculosis and Lung Disease convened a stakeholder meeting on this topic in February 2022.METHODS: Focused group discussions were informed by literature and presentations summarising experiences of obtaining inhaled medicines in LMICs. The virtual meeting was moderated using a topic guide around barriers and solutions to improve access. The thematic framework approach was used for analysis.RESULTS: A total of 58 key stakeholders, including patients, healthcare practitioners, members of national and international organisations, industry and WHO representatives attended the meeting. There were 20 pre-meeting material submissions. The main barriers identified were 1) low awareness of CRDs; 2) limited data on CRD burden and treatments in LMICs; 3) ineffective procurement and distribution networks; and 4) poor communication of the needs of people with CRDs. Solutions discussed were 1) generation of data to inform policy and practice; 2) capacity building; 3) improved procurement mechanisms; 4) strengthened advocacy practices; and 5) a World Health Assembly Resolution.CONCLUSION: There are opportunities to achieve improved access to affordable, quality-assured inhaled medicines in LMICs through coordinated, multi-stakeholder, collaborative efforts.

Thyroid storm presenting with coma

Thyroid storm is a rare manifestation of severe thyrotoxicosis, and presentation with coma is highly atypical. A 32-year-old woman, previously euthyroid, presented in a comatose state with tachycardia, hypertension and pyrexia. The patient's trachea was intubated in the community and she was subsequently admitted to the intensive care unit with a working diagnosis of meningoencephalitis. Although hypertension was present initially, subsequent hypotension necessitated a noradrenaline infusion. The patient remained persistently tachycardic and pyrexial. Initial laboratory investigations, including examination of cerebrospinal fluid, did not identify a specific diagnosis. Subsequently, raised thyroxine and triiodothyronine levels alongside undetectable thyroid-stimulating hormone confirmed the diagnosis of thyroid storm. Following treatment for thyrotoxicosis, the patient made a full recovery and was discharged from the intensive care unit after three days. This case highlights the importance of considering thyroid disease in critically ill patients presenting with non-specific symptoms.

Cystic squamous cell carcinoma of the orbit

Both primary and secondary squamous cell carcinoma (SCC) of the orbit are rare entities, though cystic SCC is even more so. It may provide a significant diagnostic conundrum to oculoplastic surgeons. We present a case of an 86 year old male with a supero-medial transilluminating cystic lesion of the orbit. There was a preceding history of a moderately differentiated SCC of the cheek, excised 3 months prior. Computed tomography (CT) demonstrated no bone erosion. The cyst was excised aided by fibrin glue. This demonstrated a poorly differentiated cystic SCC with perineural infiltration. The patient elected for palliative aspirations of the cyst and is alive 12 months later. Cystic SCC of the orbit may present to a number of specialties, including maxillofacial and orbital surgeons. Both diagnosis and management may be challenging. We review common patterns in previous cases and discuss management.

Maternal gestational weight gain and offspring's risk of cardiovascular disease and mortality

OBJECTIVE

To examine the effect of maternal gestational weight gain (GWG) on adult offspring mortality, cardiovascular morbidity and cerebrovascular morbidity.

METHODS

The Aberdeen Children of the Nineteen Fifties (ACONF) is a population-based cohort of adults born in Aberdeen, Scotland between 1950 and 1956. GWG of the mothers of cohort members was extracted from original birth records and linked to the data on offspring morbidity and mortality up to 2011 obtained from Scottish national records. HRs for cardiovascular events and mortality in offspring according to maternal weight gain in pregnancy were estimated adjusting for maternal and offspring confounders using a restricted cubic spline model.

RESULTS

After exclusions, 3781 members of the original ACONF cohort were analysed. Of these, 103 (2.7%) had died, 169 (4.5%) had suffered at least one cardiovascular event and 73 (1.9%) had had a hospital admission for cerebrovascular disease. Maternal weight gain of 1 kg/week or more was associated with increased risk of cerebrovascular event in the offspring (adjusted HR 2.70 (95% CI 1.19 to 6.12)). There was no association seen between GWG and offspring's all-cause mortality or cardiovascular event. Adult offspring characteristics (smoking, body mass index (BMI) and diabetes) were strongly associated with each outcome.

CONCLUSIONS

Maternal GWG above 0.9 kg/week may increase the risk of cerebrovascular disease in the adult offspring, but not all-cause mortality or cardiovascular disease. Health and lifestyle factors such as smoking, BMI and diabetes in the adult offspring had a stronger influence than maternal and birth characteristics on their mortality and morbidity.

Breastfeeding and introduction of complementary foods during infancy in relation to the risk of asthma and atopic diseases up to 10 years

BACKGROUND

It has been hypothesized that changes in diet during early life may have contributed to the increase in childhood asthma and atopy. The long-term effect of the timing and content of infant feeding on the incidence of asthma and atopic diseases in children is unclear.

OBJECTIVE

To investigate the associations between duration of breastfeeding and the timing of introduction of complementary foods during the first 6 months and parental-reported asthma, wheeze and atopic eczema up to 10 years of age.

METHODS

Infant feeding practices (breastfeeding and introduction of complementary foods) of 1924 singleton children participating in the Study of Eczema and Asthma To Observe the influence of Nutrition (SEATON) birth cohort were prospectively collected up to 6 months with outcomes (wheeze, atopic eczema and asthma) being assessed at 1, 2, 5 and 10 years. Data were analysed using generalized estimating equations and discrete hazards models with adjustment for confounders.

RESULTS

By 6 months, 59% and 35% of mothers had stopped exclusive and total breastfeeding, respectively. Although formula feeding was adversely associated with wheeze in the past 12 months (adjusted OR for no formula feeding: 070, 95% CI 0.50-0.97), and the introduction of biscuits/bread after 5 months of age adversely associated with atopic eczema (adjusted OR 1.34, 95% CI 1.06-1.69), these results lost their statistical significance after adjustment for multiple testing. Stratification of the results by the presence of eczema by 6 months of age and family atopic history did not substantially differ from the results of the whole study population.

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that the nature of infant feeding during the first 6 months seems not to substantially influence the long-term risk of asthma and atopic diseases in children, nor in children at high risk of atopic disease because of a family history of atopic disease.

'Sink or swim': an evaluation of the clinical characteristics of individuals with high bone mass

SUMMARY

High bone mineral density on routine dual energy X-ray absorptiometry (DXA) may indicate an underlying skeletal dysplasia. Two hundred fifty-eight individuals with unexplained high bone mass (HBM), 236 relatives (41% with HBM) and 58 spouses were studied. Cases could not float, had mandible enlargement, extra bone, broad frames, larger shoe sizes and increased body mass index (BMI). HBM cases may harbour an underlying genetic disorder.

INTRODUCTION

High bone mineral density is a sporadic incidental finding on routine DXA scanning of apparently asymptomatic individuals. Such individuals may have an underlying skeletal dysplasia, as seen in LRP5 mutations. We aimed to characterize unexplained HBM and determine the potential for an underlying skeletal dysplasia.

METHODS

Two hundred fifty-eight individuals with unexplained HBM (defined as L1 Z-score ≥ +3.2 plus total hip Z-score ≥ +1.2, or total hip Z-score ≥ +3.2) were recruited from 15 UK centres, by screening 335,115 DXA scans. Unexplained HBM affected 0.181% of DXA scans. Next 236 relatives were recruited of whom 94 (41%) had HBM (defined as L1 Z-score + total hip Z-score ≥ +3.2). Fifty-eight spouses were also recruited together with the unaffected relatives as controls. Phenotypes of cases and controls, obtained from clinical assessment, were compared using random-effects linear and logistic regression models, clustered by family, adjusted for confounders, including age and sex.

RESULTS

Individuals with unexplained HBM had an excess of sinking when swimming (7.11 [3.65, 13.84], p < 0.001; adjusted odds ratio with 95% confidence interval shown), mandible enlargement (4.16 [2.34, 7.39], p < 0.001), extra bone at tendon/ligament insertions (2.07 [1.13, 3.78], p = 0.018) and broad frame (3.55 [2.12, 5.95], p < 0.001). HBM cases also had a larger shoe size (mean difference 0.4 [0.1, 0.7] UK sizes, p = 0.009) and increased BMI (mean difference 2.2 [1.3, 3.1] kg/m(2), p < 0.001).

CONCLUSION

Individuals with unexplained HBM have an excess of clinical characteristics associated with skeletal dysplasia and their relatives are commonly affected, suggesting many may harbour an underlying genetic disorder affecting bone mass.

Antioxidants and allergic disease: a case of too little or too much?

Speculation persists as to the possible role, if any, of dietary antioxidants in allergic disease. While it has been hypothesized that the recent increase in allergic disease is a consequence of declining dietary antioxidant intake, an alternative hypothesis proposes that the increase in allergic disease is due to increasing antioxidant intake. Dietary trends are conflicting; the intake of some antioxidants has declined, for others intakes are likely to have increased. Animal model studies demonstrate that antioxidant supplementation at the time of primary and subsequent allergen exposure attenuates allergic inflammatory responses. The data from human studies are less clear. Observational epidemiological studies of humans are beset by several methodological limitations associated with the assessment of diet and predominantly focus on asthma. Most observational studies report potentially beneficial associations between dietary antioxidants and allergic outcomes, but a small minority report potentially adverse associations. Human intervention studies suggest that single antioxidant supplements confer minimal, if any clinical benefit in adults with asthma, however, there is still scope for studies in children, atopic dermatitis, allergic rhinitis (AR) and of antioxidant combinations. More recently, it has been suggested that dietary antioxidants in the developmental context of fetal and infant development influence the development childhood asthma and atopic sensitization possibly by affecting the first interactions between the neonatal immune system and allergens. While a small number of birth cohort studies have reported potentially beneficial associations between maternal intake of some antioxidants during pregnancy and childhood asthma, there is very limited data suggesting associations between maternal antioxidant intake and childhood atopic dermatitis and AR. The available epidemiological, animal, molecular and immunological data suggest that there are associations between antioxidants and asthma and to a much lesser extent, atopic dermatitis and AR. However, the exact nature of the relationships and the potential for therapeutic intervention remain unclear.

The effect of retrieval cues on post-retrieval monitoring in episodic memory: an electrophysiological study

The aim of the present experiment was to examine whether episodic retrieval and 'post-retrieval' monitoring are affected by the nature of the cue that guides a search of memory. We recorded event-related brain potentials (ERPs) from young healthy adult participants while they tried to recall studied words (e.g. 'MOTHER') with the aid of word-stem (e.g. 'MOT') and word-fragment (e.g. 'M-TH--') retrieval cues. Analyses of the behavioural data showed that while it was far more difficult to generate completions per se for the fragments, the levels of conscious, or 'explicit', recall obtained with each type of cue were statistically identical. ERP analyses focussed upon differences in neural activity evoked by each type of cue (termed 'old/new' ERP effects) during successful versus unsuccessful retrieval. The stem and fragment old/new ERP effects were remarkably similar in their time course and magnitude, and also in their scalp distribution, which changed over time as multiple neuronal populations, and hence multiple cognitive operations, became activated. These behavioural and ERP findings suggest that the cognitive operations reflected by old/new effects in cued recall tasks may be insensitive to changes in the retrieval strategy, or effort, that participants apply to monitor the episodic status of retrieved information. The findings are discussed in relation to previous ERP and functional imaging studies that have investigated task-specific features of retrieval and post-retrieval processing in episodic memory.

Recognition memory for emotionally negative and neutral words: an ERP study

Scalp recorded event-related potentials were used to investigate the neural activity elicited by emotionally negative and emotionally neutral words during the performance of a recognition memory task. Behaviourally, the principal difference between the two word classes was that the false alarm rate for negative items was approximately double that for the neutral words. Correct recognition of neutral words was associated with three topographically distinct ERP memory 'old/new' effects: an early, bilateral, frontal effect which is hypothesised to reflect familiarity-driven recognition memory; a subsequent left parietally distributed effect thought to reflect recollection of the prior study episode; and a late onsetting, right-frontally distributed effect held to be a reflection of post-retrieval monitoring. The old/new effects elicited by negative words were qualitatively indistinguishable from those elicited by neutral items and, in the case of the early frontal effect, of equivalent magnitude also. However, the left parietal effect for negative words was smaller in magnitude and shorter in duration than that elicited by neutral words, whereas the right frontal effect was not evident in the ERPs to negative items. These differences between neutral and negative words in the magnitude of the left parietal and right frontal effects were largely attributable to the increased positivity of the ERPs elicited by new negative items relative to the new neutral items. Together, the behavioural and ERP findings add weight to the view that emotionally valenced words influence recognition memory primarily by virtue of their high levels of 'semantic cohesion', which leads to a tendency for 'false recollection' of unstudied items.

The effect of encoding manipulations on neural correlates of episodic retrieval

The present experiments investigated whether the neural correlates of explicit (conscious) retrieval from episodic memory vary qualitatively according to conditions at encoding, as is predicted by current views of the neural basis of memory retrieval. Event-related potential (ERP) correlates of word stem (e.g. MOT_) cued recall were compared for items studied under different encoding conditions. In Experiment 1, encoding was either 'shallow' or 'deep' whereas in Experiment 2 the presentation modality of the study items was either visual or auditory. In both experiments robust ERP memory effects were observed for stems completed with explicitly retrieved items from each encoding condition. The effects varied in their magnitude, such that they were largest when elicited by the more memorable class of item in each experiment. The scalp distributions of the effects did not differ according to encoding condition, a finding which offers no support for the view that retrieval involves the literal reinstatement of neural activity engaged at the time of encoding. The findings instead point to the existence of a set of retrieval operations that are engaged regardless of the conditions under which retrieved information is encoded.

Electrophysiological evidence for the modulation of retrieval orientation by depth of study processing

Event-related potentials (ERPs) were employed to investigate whether brain activity elicited by retrieval cues in a memory test varies according to the encoding task undertaken at study. Two recognition memory test blocks were administered, preceded, in one case, by a "shallow" study task (alphabetic judgement) and, in the other case, by a "deep" task (sentence generation). ERPs elicited by the new words in each test block differed, the ERPs elicited in the block following the shallow study task exhibiting the more positive-going waveforms. This finding was taken as evidence that subjects adopt different "retrieval sets" when attempting to retrieve items that had been encoded in terms of alphabetic versus semantic attributes. Differences between the ERPs elicited by correctly classified old and new words (old/new effects) also varied with encoding task. The effects for deeply studied words resembled those found in previous ERP studies of recognition memory, whereas old/new effects for shallowly studied words were confined to a late-onsetting, right frontal positivity. Together, the findings indicate that the depth of study processing influences two kinds of memory-related neural activity, associated with memory search operations, and the processing of retrieved information, respectively.

The role of the right anterior prefrontal cortex in episodic retrieval

Regional brain activity was measured with H(2) (15)O PET while participants attempted to complete word-stem and word-fragment retrieval cues with previously studied words. The retrieval cue manipulation was employed to gain control over the monitoring operations associated with evaluating the episodic status of alternative cue completions. These operations were more constrained for fragments, which had fewer possible completions than each corresponding stem. In one condition (zero target), during the scanning interval none of the cues could be completed with studied items, whereas in another condition (high target), 80% of cues belonged to studied items. Relative to baseline tasks, right anterior prefrontal activity was greater for stems than for fragments in the zero target condition. The target density manipulation did not modulate right anterior prefrontal activity, but was associated with increased activity in right dorsolateral prefrontal cortex. These findings are consistent with the proposal that the right anterior prefrontal cortex supports monitoring operations during episodic retrieval tasks. In addition, the findings add to evidence suggesting that the dorsolateral and anterior right prefrontal cortex make functionally distinct contributions to episodic retrieval.

Overexpression of cyclin A and cyclin B1 proteins in astrocytomas

BACKGROUND

Cyclins are proteins that are expressed during the progression of a normal cell through the cell cycle. In a number of cancers, overexpression of cyclin A and cyclin B1 proteins has been reported, and in some instances the levels of expression correlated well with the grades of malignancy. The expression of cyclin A and cyclin B1 proteins in astrocytoma may be linked to the histologic grade or proliferative activities.

OBJECTIVE

To study the expression of cyclin A and cyclin B1 proteins in astrocytomas and correlate the labeling indices (LIs) of cyclin A and cyclin B1 with histologic grade and Ki-67 LI.

DESIGN

The surgical biopsy specimens from 65 adults with astrocytomas were reviewed and divided into grades based on the World Health Organization system. The paraffin sections were immunostained using primary antibodies against Ki-67, cyclin A, and cyclin B1. The LIs of these astrocytomas for the 3 different antibodies were determined by computerized image analysis.

RESULTS

The cyclin A LI showed good correlation with astrocytoma grade and Ki-67 LI. Both the nuclear and cytoplasmic cyclin B LIs correlated well with the tumor grade but showed poor correlation with Ki-67 LI.

CONCLUSIONS

This study suggests that although both cyclin A and B protein expression are related to the grade of malignancy in astrocytomas, cyclin A levels more generally reflect the proliferative state of these tumors. We also provide indirect evidence that cyclin B1 is associated with the aberrant progression through the G2-M phase checkpoint in astrocytomas.

Multiple feeding in wolf spiders: the effect of starvation on handling time, ingestion rate, and intercatch intervals in Lycosa lapidosa (Araneae : Lycosidae)

Multiple prey capture, the behaviour of a predator attacking prey whilst handling a previously caught item, occurs in a variety of spiders that do not build webs. The effects of recent feeding history on the frequency of multiple prey attacks, handling time, ingestion rate, and intercatch intervals were examined experimentally in the wolf spider Lycosa lapidosa McKay. Juvenile spiders were subjected to two different feeding regimes (starvation for 14 and 28 days) and then provided with two different prey types (blowflies, Lucilia cuprina, and crickets, Acheta domestica). These two starvation levels or prey types had little effect on the frequency (75%) of multiple prey attacks. Spiders ingested approximately half the weight of any captured prey, regardless of how many prey items they attacked. At the same time, the handling time per prey item decreased with an increasing number of prey attacked. This indicates a more efficient ingestion rate when more prey are consumed. While the attacking time for the first prey was the same for all treatments, the first intercatch interval was longer for spiders that were starved longer. Chronically starved L. lapidosa appear to secure a previously caught item rather than optimise their capture rate by attacking further available prey.

Versican enhances locomotion of astrocytoma cells and reduces cell adhesion through its G1 domain

Versican is a large extracellular proteoglycan and is expressed in a variety of tissues including the central nervous system. A malignant astrocytoma cell line U87 with high motility expressed a higher level of versican than another malignant astrocytoma cell line U343 with lower motility. We observed that the U87 cells were less adherent to tissue culture plates than the U343 cells. To investigate the role of versican in astrocytoma cell migration, we generated recombinant products of a mini-versican construct expressed in COS-7 cells. We found that the mini-versican products enhanced astrocytoma cell migration. Furthermore, enhanced migration was promoted by the G1 domain but not the G3 domain of versican. We introduced culture medium containing products of the mini-versican, the G1, and the G3 constructs separately into the astrocytoma cell lines U87 and U343. The mini-versican and the G1 construct, but not the G3 construct, were shown to reduce astrocytoma cell adhesion. The present data suggest that versican exerts its effect on astrocytoma cell migration and adhesion through the G1 domain.

A study of vestibular schwannomas using positron emission tomography and monoclonal antibody Ki-67

OBJECTIVE

This study aimed to evaluate the role of positron emission tomography (PET) as an in vivo determinant of tumor aggressiveness and growth.

STUDY DESIGN

The study design was a prospective pilot study.

SETTING

Positron emission tomography was performed at the Clarke Institute of Psychiatry. All patients were treated at the Sunnybrook Health Science Centre. Both institutions are affiliated with the University of Toronto, Toronto, Canada.

PATIENTS

The study consisted of five consecutive patients with vestibular schwannomas with tumor size of 1 cm or larger within the cerebellopontine angle. One was a recurrent tumor and four were primary tumors.

INTERVENTIONS

Preoperative PET studies were conducted using 18-fluorodeoxyglucose (FDG) as a radionuclide tracer to measure glucose metabolism within tumors. Tumors were processed and immunostained against Ki-67 nuclear antigen; their proliferative potentials were quantified based on immunoreactivity of tumor cells.

MAIN OUTCOME MEASURES

Tumor metabolic activity on PET was compared with that of contralateral cerebellum to arrive at an FDG index. This number was compared with clinical parameters and Ki-67 reactivity.

RESULTS

On PET, all tumors showed less metabolic activity than the cerebellum. The FDG uptake varied greatly between tumors independent of clinical parameters. All the tumors had a low proliferative index (<5%) with immunohistochemistry; there were quite a bit of intralesional variations in proliferative activities.

CONCLUSION

Large tumor size and recurrent disease did not correlate well with increased FDG uptake on PET. Similarly, they did not show increased cellular activities as expressed by Ki-67 immunostaining.

Neural correlates of cued recall with and without retrieval of source memory

A source memory procedure was used to investigate whether event-related potentials (ERPs) reflect the retrieval of episodic information (recollection) on tests of word-stem cued recall. 'Cued recall ERP effects' for recalled items were found to differ only in their magnitudes, and not their scalp distributions, according to the accuracy of source memory. This finding strongly supports the hypothesis that cued recall ERP effects reflect quantitative variation in the amount or quality of information which can be retrieved about recently experienced events. Topographic analyses also revealed that the distribution of the cued recall ERP effects changed over time, reflecting the activity of at least two temporally and neuroanatomically dissociable neural populations contributing to recollection on this task.

Neural correlates of memory retrieval during recognition memory and cued recall

Regional brain activity, measured by H215O PET, was investigated during recognition memory and word-stem cued recall of words in order to compare the neural correlates of two components of memory retrieval-effort and success-as a function of task. For each task there was a baseline and two retrieval conditions. In one retrieval condition (zero density), none of the test items corresponded to words encoded in a preceding study phase. Differences in activity between this condition and the baseline were employed to characterize the neural correlates of retrieval effort in each task. In the other retrieval condition (high density), 80% of the test items had been studied previously. Differences in brain activity between this condition and the zero-density condition were taken to represent the neural correlates of successful retrieval. The principal findings concern the right anterior prefrontal cortex, a region demonstrated previously to be active during episodic retrieval. Relative to baseline, this region showed no evidence of activation in the zero-density condition of the recognition task, but did show enhanced activity in the equivalent condition of the cued-recall task. In contrast, relative to the zero-density condition, the high-density condition was associated with increased right prefrontal activity during recognition, but reduced activity during cued recall. It is proposed that the right prefrontal cortex supports cognitive processes that operate on information retrieved in response to a test item and that these processes contribute to the evaluation of whether the information represents an appropriate prior episode.

Dissociation of the neural correlates of implicit and explicit memory

One presentation of a word to a subject is enough to change the way in which the word is processed subsequently, even when there is no conscious (explicit) memory of the original presentation. This phenomenon is known as implicit memory. The neural correlates of implicit memory have been studied previously, but they have never been compared with the correlates of explicit memory while holding task conditions constant or while using a procedure that ensured that the neural correlates were not 'contaminated' by explicit memory. Here we use scalp-recorded event-related brain potentials to identify neural activity associated with implicit and explicit memory during the performance of a recognition memory task. Relative to new words, recently studied words produced activity in three neuroanatomically and functionally dissociable neural populations. One of these populations was activated whether or not the word was consciously recognized, and its activity therefore represents a neural correlate of implicit memory. Thus, when task and memory contamination effects are eliminated, the neural correlates of explicit and implicit memory differ qualitatively.

Electrophysiological evidence for dissociable processes contributing to recollection

This paper reviews a number of studies in which we have employed event-related potentials (ERPs) to investigate the cognitive processes which contribute to conscious recollection. Across a range of tasks (including recognition memory, source memory, associative recall and word-stem cued recall) there is evidence for the proposal that recollection involves processes which are both functionally and neurologically dissociable. This evidence takes the form of temporally and topographically dissociable ERP effects, which attain their maximum amplitude when elicited by items that satisfy operational definitions for having been recollected. The ERP effects are interpreted as reflecting retrieval and post-retrieval processes which, we argue, constitute two separate components of recollection as defined within the process dissociation framework of Jacoby and colleagues. The ERP findings suggest that post-retrieval processing is particularly sensitive to task variables, implying that recollection may be neither functionally nor neurologically homogeneous.

An event-related potential study of explicit memory on tests of cued recall and recognition

The event-related potential (ERP) correlates of performance on test of word-stem cued recall and recognition memory were contrasted. ERPs elicited by stems attracting successful recall exhibited a sustained positive-going shift relative to ERPs elicited by stems completed with unstudied items. This positive shift was maximal at electrode sites on and adjacent to the midline. An equally sustained positive-going ERP modulation was observed for the recognition memory task in ERPs elicited by recognised 'old' items relative to ERPs elicited by correctly rejected 'new' items. The scalp topography of this effect shifted from a parietally distributed asymmetry favouring left hemisphere sites, to a frontally distributed effect maximal over midline and right hemisphere sites. The findings indicate that ERP correlates of explicit memory are task-dependent. The disparate ERP effects are interpreted as reflecting a common explicit retrieval mechanism which is sensitive to the nature of retrieval cues provided at test.

An event-related potential study of word-stem cued recall

Event-related potentials (ERPs) were recorded from 13 scalp sites while subjects attempted to recall studied words using word-stems. If recall failed, stems were to be completed with the first suitable word to come to mind. To distinguish between correct completions accompanied and unaccompanied by explicit memory, subjects were required to make an overt recognition ("old/new") judgement for each completion. Semantically studied words were associated with higher levels of recall and recognition than were words subjected to non-semantic study. The sole ERP effect was a sustained positive shift in ERPs evoked by stems attracting correct completions that were correctly judged to be old. The shift was anteriorly distributed, and onset was around 300 ms post stimulus. It is interpreted as a reflection of processes either contributing to, or contingent upon, explicit memory retrieval.

A motor signal and "visual" size perception

Recent models of the visual system in primates suggest that the mechanisms underlying visual perception and visuomotor control are implemented in separate functional streams in the cerebral cortex. However, a little-studied perceptual illusion demonstrates that a motor-related signal representing arm position can contribute to the visual perception of size. The illusion consists of an illusory size change in an afterimage of the hand when the hand is moved towards or away from the subject. The motor signal necessary for the illusion could be specified by feedforward and/or feedback sources (i.e. efference copy and/or proprioception/kinesthesis). We investigated the nature of this signal by measuring the illusion's magnitude when subjects moved their own arm (active condition, feedforward and feedback information available), and when arm movement was under the control of the experimenter (passive condition, feedback information available). Active and passive movements produced equivalent illusory size changes in the afterimages. However, the illusion was not obtained when an after-image of subject's hand was obtained prior to movement of the other hand from a very similar location in space. This evidence shows that proprioceptive/kinesthetic feedback was sufficient to drive the illusion and suggests that a specific three-dimensional registration of proprioceptive input and the initial afterimage is necessary for the illusion to occur.

Dementia in acute units: wandering

This is the third article in a series which looks at how nurses in acute units can manage the behaviour problems presented by people with dementia. It concentrates on wandering, and suggests reasons why people with dementia may wander, distinguishes different types of wandering patterns, and gives some pointers for effective management.

Cyclotorsion in unilateral and bilateral superior oblique paresis

We studied excyclotorsion prospectively in 12 non-strabismic normal patients, 24 patients with unilateral superior oblique paresis (SOP), and 14 patients with bilateral SOP to determine which test and position, and what amount of torsion best discriminates between bilateral and unilateral SOP. For each patient, we measured torsion at near in primary position and in 20 degrees downgaze, using both the double Maddox rod (DMR) and Bagolini lens (BL) tests. We calculated the average of three measurements for each test in each position and the differences in mean excyclotorsion between downgaze and primary position for each patient for each test. To discriminate between unilateral SOP and normal, and bilateral and unilateral SOP patients, the best test and position combination was the DMR in downgaze (P = .0001). The probability of a torsion measurement indicating a unilateral SOP rather than a normal value was 95% at 6 degrees of excyclotorsion; of bilateral rather than unilateral SOP, 90% at 20 degrees. The range in the three torsion readings within patients with either DMR or BL in either position varied up to 7 degrees.

One hundred requests for predictive testing for Huntington's disease

In Grampian region, the first 100 requests for predictive testing for Huntington's disease have been analysed. Forty-five presymptomatic predictive test results have been given, eleven families have made a decision to undergo prenatal exclusion tests, and so far eleven pregnancies have been investigated using chorion villus biopsy. This paper presents the protocol used and a descriptive analysis of those receiving results, those choosing to leave the programme, and those unable to complete it because of an unsuitable family structure or unco-operative relatives.

Importance of timing of treadmill predictors for risk stratification after myocardial infarction: a five year follow-up study

The prognostic value of information derived from clinical characteristics and exercise treadmill tests performed before discharge and repeated at three months was evaluated in 205 consecutive patients followed for five years. Recurrent myocardial infarction, unstable angina and mortality were tabulated. Survival was analyzed by the Kaplan-Meier life-table method and the Cox regression model. The major difference between the predischarge and three month intervals was the failure of exercise-induced ST depression to predict mortality from the predischarge test. However, it was predictive of mortality at three months when 76% survived five years with a positive ischemic response compared to 94% with a negative response (P less than 0.0005). In contrast, resting ST depression of at least 1 mm was associated with a very poor five year survival rate of 58.3% and 50% when assessed at both predischarge and three months (P less than 0.0005 and P less than 0.004, respectively). Selected univariately at the predischarge interval, the following characteristics were ranked in descending order of predictive power for five year mortality by discriminant analysis: history of previous infarction; exercise capacity; and ST depression on resting ECG greater than 1 mm. At three months, the same characteristics were selected. However, recurrent infarction and unstable angina were not predictable at either interval by any clinical or treadmill variable. Characteristics tending to reflect poor exercise capacity are stronger predictors of five year outcome than exercise-induced ischemia. While predischarge exercise testing for ST segment response failed to predict survival, this variable showed improved predictive power with repeat testing at three months.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrathoracic esophageal perforation with the Angelchik antireflux prosthesis: report of a new complication

Esophageal perforation associated with migration of an Angelchik antireflux prosthesis into the thorax is reported. After initial nonoperative management, this patient was treated by an esophagogastrectomy with a favorable outcome. The complications associated with this prosthesis are reviewed briefly.

Comparison of clinical and treadmill variables for the prediction of outcome after myocardial infarction

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.