Rumination, but not mood, predicts prospective memory performance: novel insights from a derived measure of trait rumination

Prospective memory (PM) is the accurate execution of an intention in the future. PM may be negatively impacted by negative affect, but the underlying mechanisms remain unclear. Rumination may increase the frequency of task-irrelevant thoughts, which deplete attentional capacity and reduce performance. To date, no studies have examined state and trait rumination on an online measure of PM. The present study examined the effects of state and trait rumination on an event-based, focal PM task embedded within a one-back task over multiple sessions. 95 non-depressed adults (18-53 years) completed measures of state/trait rumination, mood, and PM on at least two occasions. Using multi-level modelling, we found that a derived measure of trait rumination, but not an established trait rumination survey, nor negative mood, predicted poorer PM accuracy. These novel findings demonstrate that trait rumination may partially underlie the association between negative affect & PM in a non-clinical sample, and highlight the potential of online methods to study PM.

Compassion Versus Accuracy: Lenient Scoring of the Spatial Orientation Items on the Mini-mental State Exam Lowers Sensitivity

The Mini-mental State Examination (MMSE) is a commonly used screening tool for cognitive impairment. Lenient scoring of spatial orientation errors (SOEs) on the MMSE is common and negatively affects its diagnostic utility. We examined the effect of lenient SOE scoring on MMSE classification accuracy in a consecutive case series of 103 older adults (age 60 or above) clinically referred for neuropsychological evaluation. Lenient scoring of SOEs on the MMSE occurred in 53 (51.4%) patients and lowered the sensitivity by 7% to 18%, with variable gains in specificity (0% to 11%) to psychometrically operationalized cognitive impairment. Results are consistent with previous reports that lenient scoring is widespread and attenuates the sensitivity of the MMSE. Given the higher clinical priority of correctly detecting early cognitive decline over specificity, a warning against lenient scoring of SOEs (on the MMSE and other screening tools) during medical education and in clinical practice is warranted.

Multivariate Base Rates of Low Neuropsychological Test Scores in Cognitively Intact Older Adults with Subjective Cognitive Decline from a Specialist Memory Clinic

OBJECTIVE

To avoid misdiagnosing mild cognitive impairment (MCI), knowledge of the multivariate base rates (MVBRs) of low scores on neuropsychological tests is crucial. Base rates have typically been determined from normative population samples, which may differ from clinically referred samples. The current study addresses this limitation by calculating the MVBR of low or high cognitive scores in older adults who presented to a memory clinic experiencing subjective cognitive decline but were not diagnosed with MCI.

METHOD

We determined the MVBRs on the Kaplan-Baycrest Neurocognitive Assessment for 107 cognitively healthy older adults (M age = 75.81), by calculating the frequency of patients producing n scores below or above different cut-off values (i.e., 1, 1.5, 2.0, 2.5 SD from the mean), stratifying by education and gender.

RESULTS

Performing below or above cut-off was common, with more stringent cut-offs leading to lower base rates (≥1 low scores occurred in 84.1% of older adults at -1 SD, 55.1% at -1.5 SD, and 39.3% at -2 SD below the mean; ≥1 high scores occurred in 80.4% of older adults at +1 SD, 35.5% at +1.5 SD, and 16.8% at +2 SD above the mean). Higher education was associated with varying base rates. Overall, the MVBR of obtaining a low cognitive test score was higher in this clinic sample, compared with prior studies of normative samples.

CONCLUSIONS

MVBRs for clinically referred older adults experiencing memory complaints provide a diagnostic benefit, helping to prevent attributing normal variability to cognitive impairment and limiting false positive diagnoses.

The Influence of Cerebrovascular Pathology on Cluster Analysis of Neuropsychological Scores in Patients With Mild Cognitive Impairment

OBJECTIVES

The diagnostic entity of mild cognitive impairment (MCI) is heterogeneous, highlighting the need for data-driven classification approaches to identify patient subgroups. However, these approaches can be strongly determined by sample characteristics and selected measures. Here, we applied a cluster analysis to an MCI patient database from a neuropsychology clinic to determine whether the inclusion of patients with MCI with vascular pathology would result in a different classification of subgroups.

METHODS

Participants diagnosed with MCI (n = 166), vascular cognitive impairment-no dementia (n = 26), and a group of older adults with subjective cognitive concerns but no objective impairment (n = 144) were assessed using a full neuropsychological battery and other clinical measures. Cognitive measures were analyzed using a hierarchical cluster analysis and then a k-means approach, with resulting clusters compared on a range of demographic and clinical variables.

RESULTS

We found a 4-factor solution: a cognitively intact cluster, a globally impaired cluster, an amnestic/visuospatial impairment cluster, and a mild, mixed-domain cluster. Interestingly, group differences in self-reported multilingualism emerged in the derived clusters that were not observed when comparing diagnostic groups.

CONCLUSIONS

Our results were generally consistent with previous studies using cluster analysis in MCI. Including patients with primarily cerebrovascular disease resulted in subtle differences in the derived clusters and revealed new insights into shared cognitive profiles of patients beyond diagnostic categories. These profiles should be further explored to develop individualized assessment and treatment approaches.

Flipping the Script: Measuring Both Performance Validity and Cognitive Ability with the Forced Choice Recognition Trial of the RCFT

In this study we attempted to replicate the classification accuracy of the newly introduced Forced Choice Recognition trial (FCR) of the Rey Complex Figure Test (RCFT) in a clinical sample. We administered the RCFT_FCR and the earlier Yes/No Recognition trial from the RCFT to 52 clinically referred patients as part of a comprehensive neuropsychological test battery and incentivized a separate control group of 83 university students to perform well on these measures. We then computed the classification accuracies of both measures against criterion performance validity tests (PVTs) and compared results between the two samples. At previously published validity cutoffs (≤16 & ≤17), the RCFT_FCR remained specific (.84-1.00) to psychometrically defined non-credible responding. Simultaneously, the RCFT_FCR was more sensitive to examinees' natural variability in visual-perceptual and verbal memory skills than the Yes/No Recognition trial. Even after being reduced to a seven-point scale (18-24) by the validity cutoffs, both RCFT recognition scores continued to provide clinically useful information on visual memory. This is the first study to validate the RCFT_FCR as a PVT in a clinical sample. Our data also support its use for measuring cognitive ability. Replication studies with more diverse samples and different criterion measures are still needed before large-scale clinical application of this scale.

Web-Based Cognitive Testing of Older Adults in Person Versus at Home: Within-Subjects Comparison Study

Background

Web-based research allows cognitive psychologists to collect high-quality data from a diverse pool of participants with fewer resources. However, web-based testing presents unique challenges for researchers and clinicians working with aging populations. Older adults may be less familiar with computer usage than their younger peers, leading to differences in performance when completing web-based tasks in their home versus in the laboratory under the supervision of an experimenter.

Objective

This study aimed to use a within-subjects design to compare the performance of healthy older adults on computerized cognitive tasks completed at home and in the laboratory. Familiarity and attitudes surrounding computer use were also examined.

Methods

In total, 32 community-dwelling healthy adults aged above 65 years completed computerized versions of the word-color Stroop task, paired associates learning, and verbal and matrix reasoning in 2 testing environments: at home (unsupervised) and in the laboratory (supervised). The paper-and-pencil neuropsychological versions of these tasks were also administered, along with questionnaires examining computer attitudes and familiarity. The order of testing environments was counterbalanced across participants.

Results

Analyses of variance conducted on scores from the computerized cognitive tasks revealed no significant effect of the testing environment and no correlation with computer familiarity or attitudes. These null effects were confirmed with follow-up Bayesian analyses. Moreover, performance on the computerized tasks correlated positively with performance on their paper-and-pencil equivalents.

Conclusions

Our findings show comparable performance on computerized cognitive tasks in at-home and laboratory testing environments. These findings have implications for researchers and clinicians wishing to harness web-based testing to collect meaningful data from older adult populations.

Older adults with lower autobiographical memory abilities report less age-related decline in everyday cognitive function

BACKGROUND

Individuals differ in how they remember the past: some richly re-experience specific details of past episodes, whereas others recall only the gist of past events. Little research has examined how such trait mnemonics, or lifelong individual differences in memory capacities, relate to cognitive aging. We specifically examined trait episodic autobiographical memory (AM, the tendency to richly re-experience episodic details of past events) in relation to complaints of everyday cognitive functioning, which are known to increase with age. Although one might predict that individuals reporting higher trait-level episodic AM would be resistant to age-related decline in everyday function, we made the opposite prediction. That is, we predicted that those with lower trait-level episodic AM would be better equipped with compensatory strategies, practiced throughout the lifespan, to cope with age-related memory decline. Those with higher trait-level episodic AM would have enhanced sensitivity to age-related cognitive changes due to their tendency to rely on their perceived above-average memory function.

METHODS

We tested these predictions in 959 older adults aged 50-93 using online subjective and objective measures of memory and cognitive function. Our key measures of interest were the Survey of Autobiographical Memory, a measure of autobiographical memory abilities; and the Cognitive Failures Questionnaire, a measure of everyday cognitive function.

RESULTS

In keeping with our prediction, we found that complaints of day-to-day memory slips and errors (normally elevated with age) remained stable or even decreased with age among those reporting lower trait-level episodic AM, whereas those reporting higher trait-level episodic AM reported the expected age-related increase in such errors. This finding was specific to episodic AM and not observed for other autobiographical memory capacities (e.g., semantic, spatial). It was further unaccounted for by response bias or objectively assessed cognitive abilities.

CONCLUSIONS

Congenitally low trait-level episodic AM may paradoxically confer a functional advantage in aging. This could be due to well-developed non-episodic strategies not present in those with higher abilities, who are more sensitive to age-related memory decline attributable to medial temporal lobe changes. Our findings emphasize the importance of considering individual differences when studying cognitive aging trajectories.

Lactose drives Enterococcus expansion to promote graft-versus-host disease

Disruption of intestinal microbial communities appears to underlie many human illnesses, but the mechanisms that promote this dysbiosis and its adverse consequences are poorly understood. In patients who received allogeneic hematopoietic cell transplantation (allo-HCT), we describe a high incidence of enterococcal expansion, which was associated with graft-versus-host disease (GVHD) and mortality. We found that Enterococcus also expands in the mouse gastrointestinal tract after allo-HCT and exacerbates disease severity in gnotobiotic models. Enterococcus growth is dependent on the disaccharide lactose, and dietary lactose depletion attenuates Enterococcus outgrowth and reduces the severity of GVHD in mice. Allo-HCT patients carrying lactose-nonabsorber genotypes showed compromised clearance of postantibiotic Enterococcus domination. We report lactose as a common nutrient that drives expansion of a commensal bacterium that exacerbates an intestinal and systemic inflammatory disease.

Coherence and congruency mediate medial temporal and medial prefrontal activity during event construction

The precise roles of the hippocampus (HPC) and medial prefrontal cortex (mPFC) in initially constructing imagined events remains unclear. HPC activity during imagination may be modulated by mnemonic load, given its role in working memory for complex materials, and/or by the semantic relatedness (i.e. congruency) between items and their context. MPFC activation may track with congruency or mnemonic load, given the role of ventral mPFC in schema processing and the dorsal mPFC in working memory for social information. Sixteen healthy adults (M age = 22.3) underwent an event construction task, wherein participants were provided with a context and item words and imagined an event, forming as many inter-item associations as possible among the items. The stimuli varied by set size and by normatively-defined congruence (normative congruency) to explore their effects on HPC and mPFC activity and functional connectivity. We observed HPC connectivity during event construction in general, whereas dorsal mPFC connectivity occurred during imagining only at higher set sizes. Moreover, anterior hippocampal activity correlated positively with increasing coherence between items during imagining, suggesting that the anterior HPC is sensitive to the relational demands of constructing a novel event. Parahippocampal, hippocampal, temporal pole, and mPFC activity tracked only with individual differences in subjective ratings of congruency of imagined events, which may contribute to construction by retrieving existing schema-related information. Collectively, these findings provide new insights into the factors that modulate HPC and mPFC activity when constructing mental simulations.

Development of a Multicompartment Permeability-Limited Lung PBPK Model and Its Application in Predicting Pulmonary Pharmacokinetics of Antituberculosis Drugs

Achieving sufficient concentrations of antituberculosis (TB) drugs in pulmonary tissue at the optimum time is still a challenge in developing therapeutic regimens for TB. A physiologically based pharmacokinetic model incorporating a multicompartment permeability-limited lung model was developed and used to simulate plasma and pulmonary concentrations of seven drugs. Passive permeability of drugs within the lung was predicted using an in vitro-in vivo extrapolation approach. Simulated epithelial lining fluid (ELF):plasma concentration ratios showed reasonable agreement with observed clinical data for rifampicin, isoniazid, ethambutol, and erythromycin. For clarithromycin, itraconazole and pyrazinamide the observed ELF:plasma ratios were significantly underpredicted. Sensitivity analyses showed that changing ELF pH or introducing efflux transporter activity between lung tissue and ELF can alter the ELF:plasma concentration ratios. The described model has shown utility in predicting the lung pharmacokinetics of anti-TB drugs and provides a framework for predicting pulmonary concentrations of novel anti-TB drugs.

In multiple sclerosis anxiety, not depression, is related to gender

Background:

There is a high prevalence of depressive and anxiety disorders in multiple sclerosis (MS), a disease 2.5 times more frequent in females. Contrary to the general population, in whom studies have demonstrated higher rates of depression and anxiety in females, little is known about the impact of gender on psychiatric sequelae in MS patients.

Objectives:

We conducted a retrospective study to try to clarify this uncertainty.

Methods:

Demographic, illness-related and behavioral variables were obtained from a neuropsychiatric database of 896 patients with a confirmed diagnosis of MS. Symptoms of depression and anxiety were obtained with the Hospital Anxiety and Depression Scale (HADS). Gender comparisons were undertaken and predictors of depression and anxiety sought with a linear regression analysis.

Results:

HADS data were available for 711 of 896 (79.35%) patients. Notable gender differences included a higher frequency of primary progressive MS in males ( p = 0.002), higher HADS anxiety scores in females ( p < 0.001), but no differences in HADS depression scores.

Conclusion:

In MS, gender influences the frequency of anxiety only. This suggests that the etiological factors underpinning anxiety and depression in MS are not only different from one another, but also in the case of depression, different from those observed in general population samples.

Multiple sclerosis, cannabis, and cognition: A structural MRI study

Objective

A subset of patients with multiple sclerosis (MS) smoke cannabis to relieve symptoms including spasticity and pain. Recent evidence suggests that smoking cannabis further impairs cognition in people with MS and is linked to impaired functional brain changes. No such association, however, has been reported between cannabis use and structural brain changes, hence the focus of the present study.

Methods

Twenty patients with MS who smoke cannabis for symptom relief, and 19 matched non-cannabis-smoking MS patients were given the Brief Repeatable Neuropsychological Battery and structural MRI scans. Images were segmented into gray matter and white matter, and subsequently analysed with Partial Least Squares, a data-driven multivariate technique that explores brain–behaviour associations.

Results

In both groups, the Partial Least Squares analysis yielded significant correlations between cognitive scores and both gray matter (33% variance, p < .0001) and white matter (17% variance, p < .05) volume. Gray matter volume in the thalamus, basal ganglia, medial temporal, and medial prefrontal regions, and white matter volume in the fornix correlated with cognitive deficits. Crucially, the analysis indicated that brain volume reductions were associated with more extensive cognitive impairment in the cannabis versus the non-cannabis MS group.

Interpretation

These results suggest that cannabis use in MS results in more widespread cognitive deficits, which correlate with tissue volume in subcortical, medial temporal, and prefrontal regions. These are the first findings demonstrating an association between cannabis use, cognitive impairment and structural brain changes in MS patients.

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In MS, cannabis use moderates the association between cognition and brain integrity.

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Gray matter correlates with more widespread cognitive deficits in cannabis users.

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Hippocampal volume & white matter are correlated with memory only in cannabis users.

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Such differential patterns suggest that cannabis use has negative effects in MS patients.

The future is now: model-based clinical trial design for Alzheimer's disease

Failures in trials for Alzheimer's disease (AD) may be attributable to inadequate dosing, population selection, drug inefficacy, or insufficient design optimization. The Coalition Against Major Diseases (CAMD) was formed in 2008 to develop drug development tools (DDT) to expedite drug development for AD and Parkinson's disease. CAMD led a process that successfully advanced a clinical trial simulation (CTS) tool for AD through the formal regulatory review process at the US Food and Drug Administration (FDA) and European Medicines Agency (EMA).

Old wine in new bottles: validating the clinical utility of SPECT in predicting cognitive performance in mild traumatic brain injury

The neural underpinnings of cognitive dysfunction in mild traumatic brain injury (TBI) are not fully understood. Consequently, patient prognosis using existing clinical imaging is somewhat imprecise. Single photon emission computed tomography (SPECT) is a frequently employed investigation in this population, notwithstanding uncertainty over the clinical utility of the data obtained. In this study, subjects with mild TBI underwent (99m)Tc-ECD SPECT scanning, and were administered a brief battery of cognitive tests and self-report symptom scales of concussion and emotional distress. Testing took place 2 weeks (n=84) and 1 year (n=49) post-injury. Multivariate analysis (i.e., partial least squares analysis) revealed that frontal perfusion in right superior frontal and middle frontal gyri predicted poorer performance on the Stroop test, an index of executive function, both at initial and follow-up testing. Conversely, SPECT scans categorized as normal or abnormal by radiologists did not differentiate cognitively impaired from intact subjects. These results demonstrate the clinical utility of SPECT in mild TBI, but only when data are subjected to blood flow quantification analysis.

Differences in cerebral perfusion deficits in mild traumatic brain injury and depression using single-photon emission computed tomography

Background: Numerous studies have shown decreased perfusion in the prefrontal cortex following mild traumatic brain injury (mTBI). However, similar hypoperfusion can also be observed in depression. Given the high prevalence of depressive symptoms following mTBI, it is unclear to what extent depression influences hypoperfusion in TBI.

Methods: Mild TBI patients without depressive symptoms (mTBI-noD, n = 39), TBI patients with depressive symptoms (mTBI-D, n = 13), and 15 patients with major depressive disorder (MDD), but no TBI were given 99m T-ECD single-photon emission computed tomography (SPECT) scans within 2 weeks of injury. All subjects completed tests of information processing speed, complex attention, and executive functioning, and a self-report questionnaire measuring symptoms of psychological distress. Between-group comparisons of quantified SPECT perfusion were undertaken using univariate and multivariate (partial least squares) analyses.

Results: mTBI-D and mTBI-noD groups did not differ in terms of cerebral perfusion. However, patients with MDD showed hypoperfusion compared to both TBI groups in several frontal (orbitofrontal, middle frontal, and superior frontal cortex), superior temporal, and posterior cingulate regions. The mTBI-D group showed poorer performance on a measure of complex attention and working memory compared to both the mTBI-noD and MDD groups.

Conclusion: These results suggest that depressive symptoms do not affect SPECT perfusion in the sub-acute phase following a mild TBI. Conversely, MDD is associated with hypoperfusion primarily in frontal regions.

Cross-amplification of nonspecific microsatellites markers: a useful tool to study endangered/vulnerable species of southern Andes deer

Thirty-nine microsatellite loci that are highly conserved in red deer, sika deer, reindeer, Soay sheep, and other artiodactyls were tested in two vulnerable and endangered Neotropical deer (pudu: Pudu puda and huemul: Hippocamelus bisulcus) with the aim of producing a standardized set of markers that can be used successfully in noninvasive samples from these species. We also compared these nonspecific loci against eight polymorphic loci that were recently developed for huemul to determine whether the nonspecific markers could reflect the huemul's genetic variation that was observed with the specific loci. We identified 10 suitable loci, six of which constitute a standardized set for the two species and can be used to identify them in the absence of phenotypic data. The expected heterozygosity per locus for the panel of six loci ranged from 0.461 to 0.889 (average 0.665), and the maximum probability of identity value was 6.9x10(-6) and 3.2x10(-4) in pudu and huemul, respectively. This set of loci has potential applications in evolutionary, ecological, forensic, and conservation studies in pudu and huemul.

An eight component decision-making model for problem gambling: a systems approach to stimulate integrative research

Problem Gambling (PG) represents a serious problem for affected individuals, their families and society in general. Previous approaches to understanding PG have been confined to only a subset of the psychobiological factors influencing PG. We present a model that attempts to integrate potential causal factors across levels of organization, providing empirical evidence from the vast literature on PG and complimentary literatures in decision-making and addiction. The model posits that components are arranged systematically to bias decisions in favor of either immediately approaching or avoiding targets affording the opportunity for immediate reward. Dopamine, Testosterone and Endogenous Opioids favor immediate approach, while Serotonin and Cortisol favor inhibition. Glutamate is involved in associative learning between stimuli and promotes the approach response through its link to the DA reward system. GABA functions to monitor performance and curb impulsive decision-making. Finally, while very high levels of Norepinephrine can induce arousal to an extent that is detrimental to sound decision-making, the reactivity of the Norepinephrine system and its effects of Cortisol levels can shift the focus towards long-term consequences, thereby inhibiting impulsive decisions. Empirical evidence is provided showing the effects of each component on PG and decision-making across behavioural, neuropsychological, functional neuroimaging and genetic levels. Last, an effect size analysis of the growing pharmacotherapy literature is presented. It is hoped that this model will stimulate multi-level research to solidify our comprehension of biased decision-making in PG and suggest pharmacological and psychological approaches to treatment.

The Coalition Against Major Diseases: developing tools for an integrated drug development process for Alzheimer's and Parkinson's diseases

Aiming to emulate the successful accelerated development of HIV/AIDS drugs, the Critical Path Institute (C-Path), in collaboration with the Engelberg Center for Health Care Reform at the Brookings Institution, has formed the Coalition Against Major Diseases (CAMD). Members include 6 nonprofit groups representing patients' interests, 15 leading pharmaceutical companies, the US Food and Drug Administration (FDA), the European Medicines Agency (EMEA), 2 institutes of the National Institutes of Health (NIH)-the National Institute on Aging (NIA) and the National Institute of Neurological Disorders and Stroke (NINDS)-and representatives from academia. The coalition's purpose is to transform the drug development paradigm for neurodegenerative diseases and serve as a model for other major diseases.

Warfarin interactions with substances listed in drug information compendia and in the FDA-approved label for warfarin sodium

Interactions of warfarin with other drugs or substances can pose a serious problem. We assessed three drug information compendia-Clinical Pharmacology, ePocrates, and Micromedex-and the warfarin sodium (Coumadin) product label (August 2007) approved by the US Food and Drug Administration for listings of interactions between warfarin and drugs, biologics, foods, and dietary supplements. The drug information compendia and warfarin label differed greatly as to the total number of substances that interact with warfarin. Of a total of 648 entries from the four sources, only 50 were common to all the sources. The types of substances listed as interacting with warfarin were entire classes of drugs, individual drugs, and combinations; biologics; dietary supplements; foods; alcohol; and tobacco. These sources were then examined for classification by severity of interaction and the underlying evidence base. This study provides evidence that there is little concordance among commonly used drug compendia and product labels with respect to interactions involving warfarin.

Extended embryo culture to increase implantation rate

Multiple pregnancies are a serious adverse event of IVF treatment. Several strategies have been developed to improve embryo selection and embryo developmental potential to increase pregnancy rates without increasing the risk of multiple pregnancies. The only way to effectively solve this problem is to reduce the number of embryos transferred to one. The introduction of extended embryo culture has provided IVF programmes with a valuable tool to select more accurately those embryos with a higher implantation potential. The concept of single embryo transfer presents a clinical dilemma with seemingly opposing sides: one seeking to maintain acceptable pregnancy rates and the other seeking to reduce the number of twin births or high order multiple pregnancies. The present review addresses the potential benefits and drawbacks of blastocyst transfer.

Extended embryo culture to increase implantation rate

Multiple pregnancies are a serious adverse event of IVF treatment. Several strategies have been developed to improve embryo selection and embryo developmental potential to increase pregnancy rates without increasing the risk of multiple pregnancies. The only way to effectively solve this problem is to reduce the number of embryos transferred to one. The introduction of extended embryo culture has provided IVF programmes with a valuable tool to select more accurately those embryos with a higher implantation potential. The concept of single embryo transfer presents a clinical dilemma with seemingly opposing sides: one seeking to maintain acceptable pregnancy rates and the other seeking to reduce the number of twin births or high order multiple pregnancies. The present review addresses the potential benefits and drawbacks of blastocyst transfer.

A study of the lasting effects of cocaine pre-exposure on anxiety-like behaviors under baseline conditions and in response to central injections of corticotropin-releasing factor

Anxiety-like behaviors emerge with repeated exposure to and short-term withdrawal from cocaine. The stress-related neuropeptide, corticotropin-releasing factor (CRF), has been implicated in the anxiogenic effects of cocaine withdrawal, as well as in some of the long-lasting effects of cocaine. One objective of the present experiments was to determine whether repeated exposures to cocaine, under conditions that induce anxiety in the initial withdrawal period, would induce longer-lasting anxiogenic responses. A second objective was to determine whether any such effects would be potentiated by CRF. In Experiment 1, animals were injected once daily for 7 days with cocaine (30 mg/kg, i.p.) or saline in the home cages and, after a 10-day drug-free period, were given an i.c.v. injection of CRF (0.5 or 5.0 micro g) or vehicle, followed by a 5-min test for anxiety in the elevated plus maze or light-dark transition apparatus. In Experiment 2, animals were given the cocaine or saline injections in a distinct environment. At test, they were placed in the distinct environment after the CRF (0.5 micro g) or vehicle injection and were subsequently tested for anxiety. Cocaine produced enhanced levels of anxiety when pre-exposures were given in a distinct environment, but not when they were given in the home cage. In neither case did cocaine differentially alter anxiety-like responses to CRF. The results suggest that a "reminder" of the drug experience, such as re-exposure to cocaine-paired contextual cues, may be necessary to induce elevated levels of anxiety after the initial withdrawal period. In addition, although the results do not rule out a role for endogenous CRF in lasting cocaine-induced anxiogenic responses, they suggest that an increased sensitivity of CRF receptors to the peptide is not responsible for the effect.

Ductal cell carcinoma of the kidney with extensive signet ring cell mucosecreting areas. A case report with immunohistochemical analysis

We present the case of a 45-year-old patient with a renal ductal cell carcinoma arising in the Bellini ducts that was composed of histologically well-differentiated tubulopapillary and cystic areas with desmoplastic stroma, extensive mucosecreting areas, and regions depicting a transition between these two constituents. The mucosecreting component was mostly formed by signet ring tumor cells containing cytoplasmic Alcian blue-PAS-stainable mucins. The tubulopapillary and cystic areas of the tumor showed the immunohistochemical staining for low and high molecular weight cytokeratin, EMA, vimentin and Ulex europaeus, characteristic of ductal cell carcinoma. The mucosecreting cells also presented intense positive staining for cytokeratin and vimentin, and this is quite similar to observations reported in some forms of gastrointestinal cancer with rhabdoid features that are indicative of poor prognosis. Our findings suggest that mucosecreting areas with signet ring cells represent an extreme metaplastic change that can seldom occur in certain forms of renal tumors.

Maternal serum Down syndrome screening: free beta-protein is a more effective marker than human chorionic gonadotropin

The use of quantitative human chorionic gonadotropin measurement in obstetrics has a long and successful history. Prior studies on the utility of human chorionic gonadotropin in Down syndrome screening have utilized assays that measure the intact human chorionic gonadotropin molecule. This study targeted a distinct marker, the human chorionic gonadotropin free beta-protein, which is present in second-trimester maternal serum at much lower concentrations than is intact human chorionic gonadotropin. Our study of 29 cases of trisomy 21 and 450 control samples shows 80% detection efficiency with maternal serum alpha-fetoprotein, the free beta-protein, and maternal age in pregnancies under 17 weeks' gestation. We conclude that the combination of maternal serum alpha-fetoprotein and the human chorionic gonadotropin free beta-protein will be useful in the prenatal detection of trisomy 21.