Beta to theta power ratio in EEG periodic components as a potential biomarker in mild cognitive impairment and Alzheimer's dementia

BACKGROUND

Alzheimer's dementia (AD) is associated with electroencephalography (EEG) abnormalities including in the power ratio of beta to theta frequencies. EEG studies in mild cognitive impairment (MCI) have been less consistent in identifying such abnormalities. One potential reason is not excluding the EEG aperiodic components, which are less associated with cognition than the periodic components. Here, we investigate whether aperiodic and periodic EEG components are disrupted differently in AD or MCI vs. healthy control (HC) individuals and whether a periodic based beta/theta ratio differentiates better MCI from AD and HC groups than a ratio based on the full spectrum.

METHODS

Data were collected from 44 HC (mean age (SD) = 69.1 (5.3)), 114 MCI (mean age (SD) = 72.2 (7.5)), and 41 AD (mean age (SD) = 75.7 (6.5)) participants. Aperiodic and periodic components and full spectrum EEG were compared among the three groups. Receiver operating characteristic curves obtained via logistic regression classifications were used to distinguish the groups. Last, we explored the relationships between cognitive performance and the beta/theta ratios based on the full or periodic spectrum.

RESULTS

Aperiodic EEG components did not differ among the three groups. In contrast, AD participants showed an increase in full spectrum and periodic relative powers for delta, theta, and gamma and a decrease for beta when compared to HC or MCI participants. As predicted, MCI group differed from HC participants on the periodic based beta/theta ratio (Bonferroni corrected p-value = 0.036) measured over the occipital region. Classifiers based on beta/theta power ratio in EEG periodic components distinguished AD from HC and MCI participants, and outperformed classifiers based on beta/theta power ratio in full spectrum EEG. Beta/theta ratios were comparable in their association with cognition.

CONCLUSIONS

In contrast to a full spectrum EEG analysis, a periodic-based analysis shows that MCI individuals are different on beta/theta ratio when compared to healthy individuals. Focusing on periodic components in EEG studies with or without other biological markers of neurodegenerative diseases could result in more reliable findings to separate MCI from healthy aging, which would be valuable for designing preventative interventions.

Ambient Monitoring of Gait and Machine Learning Models for Dynamic and Short-Term Falls Risk Assessment in People With Dementia

Falls are a leading cause of morbidity and mortality in older adults with dementia residing in long-term care. Having access to a frequently updated and accurate estimate of the likelihood of a fall over a short time frame for each resident will enable care staff to provide targeted interventions to prevent falls and resulting injuries. To this end, machine learning models to estimate and frequently update the risk of a fall within the next 4 weeks were trained on longitudinal data from 54 older adult participants with dementia. Data from each participant included baseline clinical assessments of gait, mobility, and fall risk at the time of admission, daily medication intake in three medication categories, and frequent assessments of gait performed via a computer vision-based ambient monitoring system. Systematic ablations investigated the effects of various hyperparameters and feature sets and experimentally identified differential contributions from baseline clinical assessments, ambient gait analysis, and daily medication intake. In leave-one-subject-out cross-validation, the best performing model predicts the likelihood of a fall over the next 4 weeks with a sensitivity and specificity of 72.8 and 73.2, respectively, and achieved an area under the receiver operating characteristic curve (AUROC) of 76.2. By contrast, the best model excluding ambient gait features achieved an AUROC of 56.2 with a sensitivity and specificity of 51.9 and 54.0, respectively. Future research will focus on externally validating these findings to prepare for the implementation of this technology to reduce fall and fall-related injuries in long-term care.

Development and dissemination of an ethical guidance and person-centred isolation care planning tool to support the care of people with dementia during the COVID-19 pandemic

Background

Long‐term care (LTC) residents have been disproportionately impacted by the COVID‐19 pandemic, both from the virus itself and the restrictions in effect for infection prevention and control. Many barriers exist in LTC to prevent the effective isolation of suspect or confirmed COVID‐19 cases. Furthermore, these measures have a severe impact on the well‐being of LTC residents. Our aim was to develop a guide for long‐term care to address the ethical challenges associated with isolating dementia patients during the pandemic. The Dementia Isolation Toolkit (DIT) was developed by members of the research team in partnership with LTC stakeholders to address: 1) the practical challenges of isolating or quarantining people with dementia in a compassionate, safe, and effective manner; and 2) the need for ethical guidance to support decision‐making regarding isolation and infection control in LTC, to prevent indecision and moral distress. To develop the DIT the team reviewed and synthesized the literature on pandemic ethics in a plain‐language document, which was then reviewed by our partners and stakeholders. The final ethical guidance tool includes a discussion of the ethics around infection control measures in a pandemic, an ethical decision‐making tool, and a person‐centred isolation care planning tool. The ethical guidance tool has been downloaded more than 6500 times since it was published (bit.ly/dementiatoolkit), and has been disseminated internationally. The worksheets are being used during outbreaks to support care and decision‐making, as well as proactively, to prepare for outbreaks by developing isolation care plans. There is a need for support for ethical decision‐making in the context of a pandemic, particularly in settings such as LTC. Future studies will evaluate the implementation of the tool and its impact in addressing moral distress in health care providers in long‐term care.

Mild cognitive impairment and major depressive disorder are associated with molecular senescence abnormalities in older adults

INTRODUCTION

The biological mechanisms linking mild cognitive impairment (MCI) and major depressive disorder are not well understood. We investigated whether molecular senescence changes in older adults are associated with a history of major depressive disorder (MDD) or MCI.

METHODS

We included 371 participants: 167 with MCI; 62 cognitively normal with a history of MDD; 97 with MDD+MCI; and 45 cognitively unimpaired (CU) without a history of MDD. The candidate Senescence-Associated Secretory Phenotype (SASP) biomarkers were measured in the plasma using a customized LUMINEX assay.

RESULTS

The MDD+MCI group had a higher SASP index than the other groups (P < .001). A higher SASP index was significantly associated with worse global cognitive performance, executive dysfunction, slower processing speed, and episodic memory deficits.

DISCUSSION

Our study suggests that increased molecular changes are associated with cognitive impairment in older adults with MDD and indicate that accelerated biological aging is an underlying feature of MDD.

Measuring Gait Variables Using Computer Vision to Assess Mobility and Fall Risk in Older Adults With Dementia

Fall risk is high for older adults with dementia. Gait impairment contributes to increased fall risk, and gait changes are common in people with dementia, although the reliable assessment of gait is challenging in this population. This study aimed to develop an automated approach to performing gait assessments based on gait data that is collected frequently and unobtrusively, and analysed using computer vision methods. Recent developments in computer vision have led to the availability of open source human pose estimation algorithms, which automatically estimate the joint locations of a person in an image. In this study, a pre-existing pose estimation model was applied to 1066 walking videos collected of 31 older adults with dementia as they walked naturally in a corridor on a specialized dementia unit over a two week period. Using the tracked pose information, gait features were extracted from video recordings of gait bouts and their association with clinical mobility assessment scores and future falls data was examined. A significant association was found between extracted gait features and a clinical mobility assessment and the number of future falls, providing concurrent and predictive validation of this approach.

Examining the Link Between Cardiovascular Risk Factors and Neuropsychiatric Symptoms in Mild Cognitive Impairment and Major Depressive Disorder in Remission

BACKGROUND

Cardiovascular risk factors (CVRFs) have been linked to both depression and cognitive decline but their role in neuropsychiatric symptoms (NPS) has yet to be clarified.

OBJECTIVE

Understanding the role of CVRFs in the etiology of NPS for prospective treatments and preventive strategies to minimize these symptoms.

METHODS

We examined the distribution of NPS using the Neuropsychiatric Inventory (NPI) scores in three cohorts from the Prevention of Alzheimer's Dementia with Cognitive Remediation Plus Transcranial Direct Current Stimulation in Mild Cognitive Impairment and Depression (PACt-MD) study: older patients with a lifetime history of major depressive disorder (MDD) in remission, patients with mild cognitive impairment (MCI), and patients with combined MCI and MDD. We also examined the link between individual NPS and CVRFs, Framingham risk score, and Hachinski ischemic score in a combined sample.

RESULTS

Analyses were based on a sample of 140 subjects, 70 with MCI, 38 with MCI plus MDD, and 32 with MDD. There was no effect of age, gender, education, cognition, or CVRFs on the presence (NPI >1) or absence (NPI = 0) of NPS. Depression was the most prevalent affective NPS domain followed by night-time behaviors and appetite changes across all three diagnostic groups. Agitation and aggression correlated negatively while anxiety, disinhibition, night-time behaviors, and irritability correlated positively with CVRFs (all p-values <0.05). Other NPS domains showed no significant association with CVRFs.

CONCLUSION

CVRFs are significantly associated with individual NPI sub-scores but not with total NPI scores, suggesting that different pathologies may contribute to different NPS domains.

Functional Competence and Cognition in Individuals With Amnestic Mild Cognitive Impairment

OBJECTIVE

The objective of this study is to characterize functional competence (measure of assistance needed for independence) on Performance Assessment of Self-Care Skills (PASS) Cognitively Mediated Instrumental Activities of Daily Living (C-IADL), in individuals with amnestic mild cognitive impairment (aMCI). It aims to determine: (1) the association of functional competence on PASS C-IADL tasks with neurocognitive test performance in aMCI, (2) its ability to discriminate individuals with aMCI from healthy control (HC) individuals, and (3) its added value in discriminating aMCI from HC individuals when combined with neurocognitive test performance.

DESIGN

Cross-sectional secondary analysis of baseline data from a cohort of individuals enrolled in a clinical trial (NCT02386670).

SETTING

Five university-affiliated outpatient clinics in Toronto, Canada.

PARTICIPANTS

aMCI (N = 137) and HC (N = 51) participants, all aged 60 years or older.

METHODS

We assessed the relationship between functional competence on three C-IADL PASS tasks (shopping, bill paying, and checkbook balancing) and neurocognitive tests in 137 participants with aMCI using multiple linear regressions. Additionally, we constructed receiver operating characteristic curves to assess the role of PASS functional competence in discriminating between 137 aMCI and 51 HC participants.

RESULTS

Functional competence on PASS was significantly associated with tests of verbal memory, information processing speed, and executive function. It demonstrated 79% accuracy in discriminating aMCI from HC participants. Combining functional competence on PASS with individual neurocognitive tests significantly increased the discriminant accuracy of individual tests, and neurocognitive test scores combined with functional competence on PASS had the highest discriminant accuracy (94%).

CONCLUSION

Functional competence on PASS is predicted by the underlying cognitive deficits and possibly captures additional element of effort that could improve the diagnostic accuracy of aMCI when combined with neurocognitive tests. Thus, PASS appears to be a promising tool for assessment of functional competence in aMCI in clinical or research settings. J Am Geriatr Soc 68:1787-1795, 2020.

Vision-Based Assessment of Gait Features Associated With Falls in People With Dementia

Background

Gait impairments contribute to falls in people with dementia. In this study, we used a vision-based system to record episodes of walking over a 2-week period as participants moved naturally around their environment, and from these calculated spatiotemporal, stability, symmetry, and acceleration gait features. The aim of this study was to determine whether features of gait extracted from a vision-based system are associated with falls, and which of these features are most strongly associated with falling.

Methods

Fifty-two people with dementia admitted to a specialized dementia unit participated in this study. Thirty different features describing baseline gait were extracted from Kinect recordings of natural gait over a 2-week period. Baseline clinical and demographic measures were collected, and falls were tracked throughout the participants’ admission.

Results

A total of 1,744 gait episodes were recorded (mean 33.5 ± 23.0 per participant) over a 2-week baseline period. There were a total of 78 falls during the study period (range 0–10). In single variable analyses, the estimated lateral margin of stability, step width, and step time variability were significantly associated with the number of falls during admission. In a multivariate model controlling for clinical and demographic variables, the estimated lateral margin of stability (p = .01) was remained associated with number of falls.

Conclusions

Information about gait can be extracted from vision-based recordings of natural walking. In particular, the lateral margin of stability, a measure of lateral gait stability, is an important marker of short-term falls risk.

Diagnosis and Management of Anxiety Disorders

PURPOSE OF REVIEW

This article provides a synopsis of the current understanding of the pathophysiology of anxiety disorders, the biological and environmental risk factors that contribute to their development and maintenance, a review of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria, and a practical approach to the treatment of anxiety disorders in adults.

RECENT FINDINGS

Despite the ubiquity of anxiety, the evidence is that most individuals with an anxiety disorder are not identified and do not receive guideline-level care. In part, this may be because of the manifold clinical presentations of anxiety disorders and clinicians' lack of confidence in accurately diagnosing and treating these conditions, especially in nonpsychiatric settings. Anxiety disorders represent the complex interplay between biological, psychological, temperamental, and environmental factors. Converging lines of evidence point to dysfunction in regulating activity in the "threat circuit" in the brain as a putative common pathophysiology underlying anxiety disorders. Evidence-based treatments for anxiety disorders, such as cognitive-behavioral therapy and antidepressant medications, have been shown to regulate activity in this circuit, which consists of reciprocal connections between the dorsomedial prefrontal cortex, insula, and amygdala.

SUMMARY

Anxiety disorders are the most common class of emotional disorders and a leading cause of disability worldwide. A variety of effective treatment strategies are available, which may exert their therapeutic benefits from top-down or bottom-up modulation of the dysfunctional brain activity associated with anxiety disorders.

Brain Amyloid PET Tracer Delivery is Related to White Matter Integrity in Patients with Mild Cognitive Impairment

BACKGROUND AND PURPOSE

Amyloid deposition, tau neurofibrillary tangles, and cerebrovascular dysfunction are important pathophysiologic features in Alzheimer's disease. Pittsburgh compound B ([¹¹ C]-PIB) is a positron emission tomography (PET) radiotracer used to quantify amyloid deposition in vivo. In addition, certain models of [¹¹ C]-PIB delivery reflect cerebral blood flow rather than amyloid plaques. As cerebral blood flow and perfusion deficits are associated with white matter pathology, we hypothesized that [¹¹ C]-PIB delivery in white matter regions may reflect white matter integrity.

METHODS

We obtained [¹¹ C]-PIB-PET scans and quantified white matter hyperintensities and global fractional anisotropy on magnetic resonance images as biomarkers of white matter pathology in 34 older participants with mild cognitive impairment with or without a history of major depressive disorder. We analyzed the [¹¹ C]-PIB time-activity curve data with models associated with cerebral blood flow: the early maximum standard uptake value and the relative delivery parameter R1. We used a global white matter region of interest.

RESULTS

Both of the partial-volume corrected PET parameters were correlated with white matter hyperintensities and fractional anisotropy.

CONCLUSION

Future studies are warranted to explore whether [¹¹ C]-PIB PET is a "triple biomarker" that may provide information about amyloid deposition, cerebral blood flow, and white matter pathology.

Electroconvulsive therapy "corrects" the neural architecture of visuospatial memory: Implications for typical cognitive-affective functioning

Although electroconvulsive therapy (ECT) is a widely used and effective treatment for refractory depression, the neural underpinnings of its therapeutic effects remain poorly understood. To address this issue, here, we focused on a core cognitive deficit associated with depression, which tends to be reliably ameliorated through ECT, specifically, the ability to learn visuospatial information. Thus, we pursued three goals. First, we tested whether ECT can “normalize” the functional brain organization patterns associated with visuospatial memory and whether such corrections would predict post-ECT improvements in learning visuospatial information. Second, we investigated whether, among healthy individuals, stronger expression of the neural pattern, susceptible to adjustments through ECT, would predict reduced incidence of depression-relevant cognition and affect. Third, we sought to quantify the heritability of the ECT-correctable neural profile. Thus, in a task fMRI study with a clinical and a healthy comparison sample, we characterized two functional connectome patterns: one that typifies trait depression (i.e., differentiates patients from healthy individuals) and another that is susceptible to “normalization” through ECT. Both before and after ECT, greater expression of the trait depression neural profile was associated with more frequent repetitive thinking about past personal events (affective persistence), a hallmark of depressogenic cognition. Complementarily, post-treatment, stronger expression of the ECT-corrected neural profile was linked to improvements in visuospatial learning, a mental ability which is markedly impaired in depression. Subsequently, using data from the Human Connectome Project (HCP) (N = 333), we demonstrated that the functional brain organization of healthy participants with greater levels of subclinical depression and higher incidence of its associated cognitive deficits (affective persistence, impaired learning) shows greater similarity to the trait depression neural profile and reduced similarity to the ECT-correctable neural profile, as identified in the patient sample. These results tended to be specific to learning-relevant task contexts (working memory, perceptual relational processing). Genetic analyses based on HCP twin data (N = 128 pairs) suggested that, among healthy individuals, a functional brain organization similar to the one normalized by ECT in the patient sample is endogenous to cognitive contexts that require visuospatial processing that extends beyond the here-and-now. Broadly, the present findings supported our hypothesis that some of the therapeutic effects of ECT may be due to its correcting the expression of a naturally occurring pattern of functional brain organization that facilitates integration of internal and external cognition beyond the immediate present. Given their substantial susceptibility to both genetic and environmental effects, such mechanisms may be useful both for identifying at risk individuals and for monitoring progress of interventions targeting mood-related pathology.

•

Trait depression and ECT-correctable neural profiles were described in patients.

•

The former was related to rumination and the latter to improved learning after ECT.

•

Their relative expression was linked to subclinical depression in a healthy sample.

•

Twin analyses implied that both profiles are endogenous to working memory contexts.

Changes in Theta but not Alpha Modulation Are Associated with Impairment in Working Memory in Alzheimer's Disease and Mild Cognitive Impairment

While several studies have found that neural oscillations play a key role in the functioning of working memory, the nature of aberrant oscillatory activity underlying working memory impairments in Alzheimer's disease (AD) and mild cognitive impairment (MCI) remains largely unexplored. These individuals often display structural alterations in brain regions and pathways involved in working memory processes and therefore may also display altered oscillatory activity during memory activation. Electroencephalographic (EEG) activity was recorded during the N-back working memory task in three groups: AD (n = 29), MCI (n = 100), and healthy controls (HCs; n = 40). Theta (4-7 Hz) and alpha (7.5-12 Hz) modulation was measured in response to the stimulus presentation during correct and incorrect responses. This modulation represents the change in EEG activity associated with the stimulus onset and was measured as a ratio of post stimulus power to pre stimulus power. We also assessed the relationship between change in oscillatory power and working memory performance. Compared to HCs, the AD group demonstrated the lowest working memory accuracy and a smaller theta ratio for correct responses on the 2-back condition; the MCI group demonstrated a smaller theta ratio for correct responses on the 3-back condition. Finally, we observed that the theta ratio, but not the alpha ratio, was a significant predictor of working memory performance in the three groups for all conditions. Taken together, these behavioral and electrophysiological results suggest that in addition to impairments in working memory performance, modulation of theta, but not alpha power, may be impaired in MCI and AD.

Theta-Gamma Coupling and Working Memory in Alzheimer's Dementia and Mild Cognitive Impairment

Working memory deficits are common among individuals with Alzheimer's dementia (AD) or mild cognitive impairment (MCI). Yet, little is known about the mechanisms underlying these deficits. Theta-gamma coupling-the modulation of high-frequency gamma oscillations by low-frequency theta oscillations-is a neurophysiologic process underlying working memory. We assessed the relationship between theta-gamma coupling and working memory deficits in AD and MCI. We hypothesized that: (1) individuals with AD would display the most significant working memory impairments followed by MCI and finally healthy control (HC) participants; and (2) there would be a significant association between working memory performance and theta-gamma coupling across all participants. Ninety-eight participants completed the N-back working memory task during an electroencephalography (EEG) recording: 33 with AD (mean ± SD age: 76.5 ± 6.2), 34 with MCI (mean ± SD age: 74.8 ± 5.9) and 31 HCs (mean ± SD age: 73.5 ± 5.2). AD participants performed significantly worse than control and MCI participants on the 1- and 2-back conditions. Regarding theta-gamma coupling, AD participants demonstrated the lowest level of coupling followed by the MCI and finally control participants on the 2-back condition. Finally, a linear regression analysis demonstrated that theta-gamma coupling (β = 0.69, p < 0.001) was the most significant predictor of 2-back performance. Our results provide evidence for a relationship between altered theta-gamma coupling and working memory deficits in individuals with AD and MCI. They also provide insight into a potential mechanism underlying working memory impairments in these individuals.

Autobiographical episodic memory in major depressive disorder

Autobiographical memory in major depression has been characterized as overgeneralized, with patients recalling few episodic details, prioritizing general schematic events. However, whether this effect reflects impaired episodic or semantic memory, or domain-general cognitive processes, is unknown. We used the Autobiographical Interview (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) to derive episodic and semantic contributions to autobiographical memory in patients with severe major depression. We also assessed memory for public events and famous people. Depressed patients were impaired on episodic, but not semantic, autobiographical memory from 2 weeks to 10 years before testing. They were also impaired on memory for public events, possibly because they followed the news less than controls. Patients' memory for famous names was not impaired, although this was strongly associated with non-episodic memories to a greater degree than in controls. The findings suggest a specific impairment of episodic autobiographical memory in depression that is not fully accounted for by domain-general processes involved in strategic retrieval.

Resting-state cortico-thalamic-striatal connectivity predicts response to dorsomedial prefrontal rTMS in major depressive disorder

Despite its high toll on society, there has been little recent improvement in treatment efficacy for major depressive disorder (MDD). The identification of biological markers of successful treatment response may allow for more personalized and effective treatment. Here we investigate whether resting-state functional connectivity predicted response to treatment with repetitive transcranial magnetic stimulation (rTMS) to dorsomedial prefrontal cortex (dmPFC). Twenty-five individuals with treatment-refractory MDD underwent a 4-week course of dmPFC-rTMS. Before and after treatment, subjects received resting-state functional MRI scans and assessments of depressive symptoms using the Hamilton Depresssion Rating Scale (HAMD17). We found that higher baseline cortico-cortical connectivity (dmPFC-subgenual cingulate and subgenual cingulate to dorsolateral PFC) and lower cortico-thalamic, cortico-striatal, and cortico-limbic connectivity were associated with better treatment outcomes. We also investigated how changes in connectivity over the course of treatment related to improvements in HAMD17 scores. We found that successful treatment was associated with increased dmPFC-thalamic connectivity and decreased subgenual cingulate cortex-caudate connectivity, Our findings provide insight into which individuals might respond to rTMS treatment and the mechanisms through which these treatments work.

Liraglutide suppresses postprandial triglyceride and apolipoprotein B48 elevations after a fat-rich meal in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled, cross-over trial

AIMS

Postprandial triglyceridaemia is a risk factor for cardiovascular disease (CVD). This study investigated the effects of steady-state liraglutide 1.8 mg versus placebo on postprandial plasma lipid concentrations after 3 weeks of treatment in patients with type 2 diabetes mellitus (T2DM).

METHODS

In a cross-over trial, patients with T2DM (n = 20, 18-75 years, BMI 18.5-40 kg/m²) were randomized to once-daily subcutaneous liraglutide (weekly dose escalation from 0.6 to 1.8 mg) and placebo. After each 3-week period, a standardized fat-rich meal was provided, and the effects of liraglutide on triglyceride (primary endpoint AUC(0-8h)), apolipoprotein B48, non-esterified fatty acids, glycaemic responses and gastric emptying were assessed. ClinicalTrials.gov ID: NCT00993304.

FUNDING

Novo Nordisk A/S.

RESULTS

After 3 weeks, mean postprandial triglyceride (AUC(0-8h) liraglutide/placebo treatment-ratio 0.72, 95% CI [0.62-0.83], p = 0.0004) and apolipoprotein B48 (AUC(0-8h) ratio 0.65 [0.58-0.73], p < 0.0001) significantly decreased with liraglutide 1.8 mg versus placebo, as did iAUC(0-8h) and C(max) (p < 0.001). No significant treatment differences were observed for non-esterified fatty acids. Mean postprandial glucose and glucagon AUC(0-8h) and C(max) were significantly reduced with liraglutide versus placebo. Postprandial gastric emptying rate [assessed by paracetamol absorption (liquid phase) and the ¹³C-octanoate breath test (solid phase)] displayed no treatment differences. Mean low-density lipoprotein and total cholesterol decreased significantly with liraglutide versus placebo.

CONCLUSIONS

Liraglutide treatment in patients with T2DM significantly reduced postprandial excursions of triglyceride and apolipoprotein B48 after a fat-rich meal, independently of gastric emptying. Results indicate liraglutide's potential to reduce CVD risk via improvement of postprandial lipaemia.

The once-daily human GLP-1 analogue liraglutide impacts appetite and energy intake in patients with type 2 diabetes after short-term treatment

The aim was to investigate effects of liraglutide on appetite and energy intake in a randomized, placebo-controlled, double-blind, crossover study. Eighteen subjects with type 2 diabetes were assigned to treatment with once-daily subcutaneous liraglutide (increasing by weekly 0.6 mg increments) or placebo for 3 weeks. Appetite ratings were assessed using visual analogue scales during a 5-h meal test. Energy and macronutrient intake during the subsequent ad libitum lunch were also measured. After 3 weeks, mean postprandial and minimum hunger ratings were significantly lower with liraglutide 1.8 mg than placebo (p < 0.01), and the mean overall appetite score was significantly higher (p = 0.05), indicating reduced appetite. Liraglutide was associated with higher maximum fullness ratings (p = 0.001) and lower minimum ratings of prospective food consumption (p = 0.01). Mean estimated energy intake was 18% lower for liraglutide than placebo [estimated ratio 0.82 (95% CI 0.73;0.94); p = 0.004], but no significant differences in macronutrient distribution were noted. Findings suggest that reduced appetite and energy intake may contribute to liraglutide-induced weight loss.

Improving recognition of late life anxiety disorders in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition: observations and recommendations of the Advisory Committee to the Lifespan Disorders Work Group

BACKGROUND

Recognition of the significance of anxiety disorders in older adults is growing. The revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM) provides a timely opportunity to consider potential improvements to diagnostic criteria for psychiatric disorders for use with older people. The authors of this paper comprise the Advisory Committee to the DSM5 Lifespan Disorders Work Group, the purpose of which was to generate informative responses from individuals with clinical and research expertise in the field of late-life anxiety disorders.

METHODS

This paper reviews the unique features of anxiety in later life and synthesizes the work of the Advisory Committee.

RESULTS

Suggestions are offered for refining our understanding of the effects of aging on anxiety and other disorders (e.g., mood disorders) and changes to the DSM5 criteria and text that could facilitate more accurate recognition and diagnosis of anxiety disorders in older adults. Several of the recommendations are not limited to the study of anxiety but rather are applicable across the broader field of geriatric mental health.

CONCLUSIONS

DSM5 should provide guidelines for the thorough assessment of avoidance, excessiveness, and comorbid conditions (e.g., depression, medical illness, cognitive impairment) in anxious older adults.

Factors associated with non-completion in a double-blind randomized controlled trial of olanzapine plus sertraline versus olanzapine plus placebo for psychotic depression

High rates of attrition have been reported in randomized controlled trials of patients with severe psychiatric illness, including psychotic depression (MDpsy). The purpose of this study is to examine factors associated with overall attrition and with subtypes of attrition in the Study of the Pharmacotherapy of Psychotic Depression (STOP-PD). Secondary analysis of data collected in a multi-site, randomized, placebo-controlled trial. Clinical services of academic hospitals. Participants comprised 259 persons with MDpsy, aged 18-93 years. The intervention consisted of the random allocation to 12 weeks of treatment of either olanzapine plus sertraline or olanzapine plus placebo. Demographic and clinical variables associated with overall non-completion and sub-types of non-completion of randomized treatment. One hundred and seventeen (45.2%) subjects did not complete 12 weeks of randomized treatment. In a logistic regression analysis, inpatient entry status, olanzapine monotherapy, and higher cumulative medical burden were statistically significant independent predictors of overall non-completion. In a multinomial logistic regression model that examined predictors of subtypes of non-completion, subjects who entered the study as an inpatient were less likely to complete because of inadequate efficacy as determined by the investigator, and older subjects were less likely to complete because of poorer tolerability. Subjects who were assigned to olanzapine monotherapy, younger subjects, and subjects who entered the study as inpatients were less likely to complete because of reasons other than efficacy or tolerability. Understanding factors that contribute to premature discontinuation in studies of MDpsy, and to the specific reasons for attrition, has the potential to improve the management of this disorder, as well as improve the design of future clinical trials of MDpsy.

Transferring preterm infants from incubators to open cots at 1600 g: a multicentre randomised controlled trial

OBJECTIVES

To determine the effects on weight gain and temperature control of transferring preterm infants from incubators to open cots at a weight of 1600 g versus a weight of 1800 g.

DESIGN

Randomised controlled trial.

SETTING

One tertiary and two regional neonatal units in public hospitals in Queensland, Australia.

PARTICIPANTS

182 preterm infants born with a birth weight less than 1600 g, who were at least 48 h old; had not required ventilation or continuous positive airways pressure within the last 48 h; were medically stable with no oxygen requirement, or significant apnoea or bradycardia; did not require phototherapy; and were enterally fed with an intake (breast milk/formula) of at least 60 ml/kg/day.

INTERVENTIONS

Transfer into an open cot at 1600 or 1800 g.

MAIN OUTCOME MEASURES

The primary outcomes were temperature stability and average daily weight gain over the first 14 days following transfer to an open cot.

RESULTS

90 infants in the 1600 g group and 92 infants in the 1800 g group were included in the analysis. Over the first 72 h, more infants in the 1800 g group had temperatures <36.4°C than the 1600 g group (p=0.03). From post-transfer to discharge, the 1600 g group had more temperatures >37.1°C (p=0.02). Average daily weight gain in the 1600 g group was 17.07 (SD±4.5) g/kg/day and in the 1800 g group, 13.97 (SD±4.7) g/kg/day (p=<0.001).

CONCLUSIONS

Medically stable, preterm infants can be transferred to open cots at a birth weight of 1600 g without any significant adverse effects on temperature stability or weight gain.

TRIAL REGISTRATION

ACTRN12606000518561 (http://www.anzctr.org.au).

Serotonin transporter occupancy and the functional neuroanatomic effects of citalopram in geriatric depression

OBJECTIVES

The functional neuroanatomic changes associated with selective serotonin reuptake inhibitor (SSRI) treatment have been the focus of positron emission tomography (PET) studies of cerebral glucose metabolism in geriatric depression.

DESIGN

To evaluate the underlying neurochemical mechanisms, both cerebral glucose metabolism and serotonin transporter (SERT) availability were measured before and during treatment with the SSRI, citalopram. It was hypothesized that SERT occupancy would be observed in cortical and limbic brain regions that have shown metabolic effects, as well as striatal and thalamic regions that have been implicated in prior studies in midlife patients.

SETTING

Psychiatric outpatient clinic.

PARTICIPANTS

Seven depressed patients who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for current major depressive episode were enrolled.

INTERVENTION

Patients underwent a 12-week open-label trial of the SSRI, citalopram.

MEASUREMENTS

Patients underwent high-resolution research tomography PET scans to measure changes in cerebral glucose metabolism and SERT occupancy by citalopram treatment (after 8-10 weeks of treatment).

RESULTS

Three different tracer kinetic models were applied to the [¹¹C]-DASB region-of-interest data and yielded similar results of an average of greater than 70% SERT occupancy in the striatum and thalamus during citalopram treatment. Voxel-wise analyses showed significant SERT occupancy in these regions, as well as cortical (e.g., anterior cingulate, superior and middle frontal, precuneus, and limbic (parahippocampal gyrus) areas that also showed reductions in glucose metabolism.

CONCLUSION

The findings suggest that cortical and limbic SERT occupancy may be an underlying mechanism for the regional cerebral metabolic effects of citalopram in geriatric depression.

Human skeletal muscle ceramide content is not a major factor in muscle insulin sensitivity

AIMS/HYPOTHESIS

In skeletal muscle, ceramides may be involved in the pathogenesis of insulin resistance through an attenuation of insulin signalling. This study investigated total skeletal muscle ceramide fatty acid content in participants exhibiting a wide range of insulin sensitivities.

METHODS

The middle-aged male participants (n=33) were matched for lean body mass and divided into four groups: type 2 diabetes (T2D, n=8), impaired glucose tolerance (IGT, n=9), healthy controls (CON, n=8) and endurance-trained (TR, n=8). A two step (28 and 80 mU m(-2) min(-1)) sequential euglycaemic-hyperinsulinaemic clamp was performed for 120 and 90 min for step 1 and step 2, respectively. Muscle biopsies were obtained from vastus lateralis at baseline, and after steps 1 and 2.

RESULTS

Glucose infusion rates increased in response to insulin infusion, and significant differences were present between groups (T2D<IGT<CON<TR). At baseline, muscle ceramide content was 108+/-7, 95+/-6, 126+/-12 and 156+/-25 nmol total ceramide fatty acids/g wet weight of tissue in the T2D, IGT, CON and TR groups, respectively, and muscle ceramide content was higher (p<0.01) in the TR than the IGT group. Muscle ceramide content was not influenced by insulin infusion. Interestingly, a positive correlation (r=0.42, p<0.05) was present between muscle ceramide content at baseline and insulin sensitivity.

CONCLUSIONS/INTERPRETATION

Total muscle ceramide content was similar between individuals showing marked differences in insulin sensitivity, and therefore does not seem to be a major factor in muscle insulin resistance. Furthermore, aerobic capacity does not appear to influence muscle ceramide content.

No effect of inhibition of insulin secretion by diazoxide on weight loss in hyperinsulinaemic obese subjects during an 8-week weight-loss diet

AIM

Obesity is positively associated with hyperinsulinaemia, and it has been suggested that hyperinsulinaemia may contribute to maintain the obese state in insulin-resistant obese individuals. The aim of the present study was to investigate the effect of inhibition of insulin secretion by diazoxide on weight loss in obese, normoglycaemic (fasting plasma glucose of > or =6.1 mmol/l), hyperinsulinaemic (fasting plasma insulin of > or =100 pmol/l) adults during a 2.5 MJ/day energy-deficient diet.

METHODS

In an 8-week, double-blind, placebo-controlled parallel design, 35 overweight and obese subjects (age: 23-54 years, body mass index: 27-66 kg/m(2)) were randomized either to 2 mg/kg/day (maximum 200 mg/day) of oral diazoxide or to placebo. Body composition and resting energy expenditure (REE) were measured before and after the intervention. Blood samples, and appetite sensations by visual analogue scales, were collected during fasting, during an oral glucose tolerance test (OGTT) and 4 h postprandially after a test meal. Subsequently, an ad libitum meal was given.

RESULTS

Thirty-one subjects completed the protocol. Eight weeks of diazoxide decreased incremental area under the response curve (iAUC) for insulin (iAUC(insulin)) and for C-peptide (iAUC(C-peptide)) and increased iAUC for glucose (iAUC(glucose)) during the OGTT and the test meal compared with the use of placebo (p < 0.003). No differences in changes between the groups in body weight, body fat, REE or appetite were observed during the 8-week trial.

CONCLUSION

These findings do not suggest that hyperinsulinaemia per se contributes to maintenance of the obese state, and insulin secretion inhibition seems not a promising drug target.

Cup feeding versus other forms of supplemental enteral feeding for newborn infants unable to fully breastfeed

BACKGROUND

Breast milk provides optimal nutrition for newborn infants, and the ideal way for infants to receive breast milk is through suckling at the breast. Unfortunately, this may not always be possible, as there are numerous reasons why a newborn infant may not be able to breastfeed and, as a result, require supplemental feeding. Currently, there are a variety of ways in which newborn infants can receive supplemental feeds. Traditionally, bottles and nasogastric tubes have been used; however, more recently, cup feeding has become a popular practice in many nurseries in an attempt to improve breastfeeding rates. There is no consistency to guide the choice of supplementation.

OBJECTIVES

To determine the effects of cup feeding versus other forms of supplemental enteral feeding on weight gain and achievement of successful breastfeeding in newborn infants who are unable to fully breastfeed.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006), CINAHL (1982 - April 2006) and MEDLINE (1966 - April 2006).

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing cup feeding to other forms of enteral feeding for the supplementation of newborn infants.

DATA COLLECTION AND ANALYSIS

Quality assessments and data extraction for included trials were conducted independently by the review authors. Outcomes reported from these studies were: weight gain, proportion not breastfeeding at hospital discharge, proportion not feeding at three months of age, proportion not feeding at six months of age, proportion not fully feeding at hospital discharge, proportion not fully breastfeeding at three months of age, proportion not fully breastfeeding at six months of age, average time per feed (minutes), length of stay and physiological events of instability such as bradycardia, apnea, and low oxygen saturation. For continuous variables such as weight gain, mean differences and 95% confidence intervals were reported. For categorical outcomes such as mortality, the relative risks (RR) and 95% confidence intervals were reported.

MAIN RESULTS

Four studies were eligible for inclusion. The experimental intervention was cup feeding and the control intervention was bottle feeding in all four studies included in this review. There was no statistically significant difference in the incidence of not breastfeeding at hospital discharge in three included studies (typical RR 0.82, 95% CI 0.62, 1.09) and not breastfeeding at three months in two included studies (typical RR 0.88, 95% CI 0.76, 1.03) or six months for the one study that reported this outcome (RR 0.91, 95% CI 0.78, 1.05). There was a statistically significant difference in not fully breastfeeding at hospital discharge (from three included studies) in favour of cup feeding (typical RR 0.75, 95% CI 0.61, 0.92). However, this was not statistically significant at three months (one study, RR 1.18, 95% CI 0.88, 1.58) or six months (one study, RR 1.31, 95% CI 0.89, 1.92). There was no statistically significant difference in weight gain from one study that reported this outcome (MD -0.60, 95% CI -3.21, 2.01). In the one study that assessed it, there was a significantly increased length of hospital stay in the cup fed infants [mean difference between groups was 10.1 days (95% CI 3.9, 16.3)]. Time to full breastfeeding was not assessed in any study.

AUTHORS' CONCLUSIONS

Cup feeding cannot be recommended over bottle feeding as a supplement to breastfeeding because it confers no significant benefit in maintaining breastfeeding beyond hospital discharge and carries the unacceptable consequence of a longer stay in hospital.

Panic disorder in the elderly

Despite being the most common group of mental disorders in later life, anxiety disorders in the elderly have historically been a neglected area of research. While clinically important, there have been few studies of anxiety disorders specifically in older persons. However, in recent years, there has been increasing interest and a growing base of studies addressing the epidemiology, comorbidity and treatment of late-life anxiety. The literature on panic disorder in the elderly is illustrative of this trend. Although clinicians who treat panic disorder in the elderly have been left to extrapolate from data derived from younger individuals with panic disorder, the last decade has witnessed the first trials of psychotherapeutic and pharmacological treatments performed exclusively in older patients. Although much work remains to be done in terms of testing both psychosocial and medication treatment strategies in rigorously designed studies, preliminary evidence suggests that both psychotherapeutic and pharmacological treatment can be effective for panic disorder in the elderly.

Continuous infusion versus intermittent flushing to prevent loss of function of peripheral intravenous catheters used for drug administration in newborn infants

BACKGROUND

The use of peripheral intravenous cannulae is common in newborn babies. Many of them require an intravenous line only for medications and not for fluid. Currently there is little uniformity in methods used to maintain cannula patency.

OBJECTIVES

The object of this review was to determine which method was better for maintaining intravenous lines used in neonates for intravenous medication only: intermittent flushing or continuous infusion

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2004), CINAHL (from 1982 to June 2004) and MEDLINE (from 1966 to June 2004) .

SELECTION CRITERIA

Randomised controlled trials comparing continuous infusion to intermittent flushing to maintain patency of intravenous cannulas. Units of randomisation might include individual catheters or individual babies.

DATA COLLECTION AND ANALYSIS

Three reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Two studies were eligible for inclusion. In one study only one of our primary outcomes was available: the duration of cannula patency for the first cannula used per infant was slightly longer in the continuous infusion group, but not significantly so, with a mean difference of -4.3 hours (95% CI -18.2 to 9.7). In the second study, only one of our primary outcomes was available: the mean (SD) number cannulas used per infant in the first 48 hours was less in the intermittent flush group with a mean difference of -0.76 cannulas (95% CI -1.37 to -0.15). No results were available for any of our other primary outcomes: in the published report, results were reported per catheter rather than per infant, a number of infants received more than one intravenous catheter (39 infants received an unknown number of catheters). The overall duration of cannula patency was significantly longer in the intermittent flush group with a mean duration of patency in the intermittent flush group of 2.1 days (SD 1.0) compared with the continuous infusion group where the mean duration of patency was 1.0 days (SD 0.5) - Student's t test P value 0.0003.

AUTHORS' CONCLUSIONS

It is difficult to draw reliable conclusions given the way the data were analysed and reported in the two included studies. The reliability of the results is uncertain. However, given the caution in interpreting these data, it should also be noted that the use of intermittent flushes was not associated in either study with a decreased cannula life or any other disadvantages, thus lending some support for the use of intermittent flushing of cannulas in a selected population in neonatal nurseries.

Side Population cells isolated from different tissues share transcriptome signatures and express tissue-specific markers

Side Population (SP) cells, isolated from murine adult bone marrow (BM) based on the exclusion of the DNA dye Hoechst 33342, exhibit potent hematopoietic stem cell (HSC) activity when compared to Main Population (MP) cells. Furthermore, SP cells derived from murine skeletal muscle exhibit both hematopoietic and myogenic potential in vivo. The multipotential capacity of SP cells isolated from variable tissues is supported by an increasing number of studies. To investigate whether the SP phenotype is associated with a unique transcriptional profile, we characterized gene expression of SP cells isolated from two biologically distinct tissues, bone marrow and muscle. Comparison of SP cells with differentiated MP cells within a tissue revealed that SP cells are in an active transcriptional and translational status and underexpress genes reflecting tissue-specific functions. Direct comparison of gene expression of SP cells isolated from different tissues identified genes common to SP cells as well as genes specific to SP cells within a particular tissue and further define a muscle and bone marrow environment. This study reports gene expression of muscle SP cells, common features and differences between SP cells isolated from muscle and bone marrow, and further identifies common signaling pathways that might regulate SP cell functions.

Pharmacotherapy of bipolar disorder in old age: review and recommendations

The authors reviewed the evidence-base for pharmacological treatment of mania and bipolar (BP) depression in late life. Treatment benefits and side effects may be modified by age-associated factors, such as neurocognitive impairments. Lithium and divalproex have most often been studied in elderly patients, and both may be efficacious in acute treatment of mania, but there are no controlled efficacy or effectiveness trials. The role of atypical antipsychotic agents remains to be clarified. Similarly, there are no systematic studies of the treatment of BP depression in elderly patients. The authors make suggestions for management and delineate priorities for research.

Lower glucose-dependent insulinotropic polypeptide (GIP) response but similar glucagon-like peptide 1 (GLP-1), glycaemic, and insulinaemic response to ancient wheat compared to modern wheat depends on processing

OBJECTIVE

To test the hypothesis that bread made from the ancient wheat Einkorn (Triticum monococcum) reduces the insulin and glucose responses through modulation of the gastrointestinal responses of glucose-dependent insulinotrophic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) compared to the responses to bread of modern wheat (Triticum aestivum).

DESIGN

The 3-h postprandial insulinaemic, glycaemic, GIP, and GLP-1 responses to bread made from Einkorn were compared to responses to a traditional Danish wheat loaf. The bread from Einkorn was prepared by 3 different processing methods: leavening with honey-salt added, leavening crushed whole grain, and conventional leavening with yeast added. Bread made from modern wheat was prepared by conventional leavening with yeast added.

SUBJECTS

A total of 11 healthy young men.

RESULTS

The postprandial GIP response was significantly (P<0.001) reduced by the Einkorn breads processed with honey-salt leavening and by using crushed whole grain bread compared to the yeast leavened bread made from modern wheat or from Einkorn. No significant differences were found in the responses of GLP-1, insulin or glucose.

CONCLUSION

Einkorn honey-salt leavened and Einkorn whole grain bread elicit a reduced gastrointestinal response of GIP compared to conventional yeast bread. No differences were found in the glycaemic, insulinaemic and GLP-1 responses. Processing of starchy foods such as wheat may be a powerful tool to modify the postprandial GIP response.

Effect of sensory perception of foods on appetite and food intake: a review of studies on humans

OBJECTIVE

How much do the sensory properties of food influence the way people select their food and how much they eat? The objective of this paper is to review results from studies investigating the link between the sensory perception of food and human appetite regulation.

CONTENT OF THE REVIEW

The influence of palatability on appetite and food intake in humans has been investigated in several studies. All reviewed studies have shown increased intake as palatability increased, whereas assessments of the effect of palatability using measures of subjective appetite sensations have shown diverging results, for example, subjects either feel more hungry and less full after a palatable meal compared to a less palatable meal, or they feel the opposite, or there is no difference. Whether palatability has an effect on appetite in the period following consumption of a test meal is unclear. Several studies have investigated which sensory properties of food are involved in sensory-specific satiety. Taste, smell, texture and appearance-specific satieties have been identified, whereas studies on the role of macronutrients and the energy content of the food in sensory-specific satiety have given equivocal results. Different studies have shown that macronutrients and energy content play a role in sensory-specific satiety or that macronutrients and energy content are not a factor in sensory-specific satiety. Sensory-specific satiety may have an important influence on the amount of food eaten. Studies have shown that increasing the food variety can increase food and energy intake and in the short to medium term alter energy balance. Further knowledge about the importance of flavour in appetite regulation is needed, for example, which flavour combinations improve satiety most, the possible connection between flavour intensity and satiety, the effect of persistence of chemesthetic sensation on palatability and satiety, and to what extent genetic variation in taste sensitivity and perception influences dietary habits and weight control.

No effect of physiological concentrations of glucagon-like peptide-2 on appetite and energy intake in normal weight subjects

OBJECTIVE

To examine the effect of a GLP-2 infusion on appetite sensations and ad libitum energy intake in healthy, normal weight humans.

DESIGN

The experiment was performed in a randomised, blinded, and placebo-controlled crossover design. Placebo or GLP-2 was infused (infusion rate of 25 pmol/kg body wth) for 4.5 h.

SUBJECTS

A total of 18 healthy, normal weight young subjects participated; eight women and 10 men.

MEASUREMENTS

During the infusion, subjects recorded their appetite sensations every 30 min using visual analogue scales, and blood was sampled frequently. After 2 h of infusion, an ad libitum meal, consisting of sandwiches, was served.

RESULTS

The concentration of GLP-2 was significantly higher during the GLP-2 infusion compared with placebo (P<0.0001) and increased further in both conditions in response to the meal. Neither appetite sensations, nor palatability of the test meals, or energy intake were different on the two occasions. Glucose, GLP-1, insulin, and GIP responses were also unaffected by the infusion, whereas glucagon levels were higher during the GLP-2 treatment (P<0.05).

CONCLUSION

Circulating GLP-2 in physiological concentrations does not seem to play a significant role in human appetite regulation.

Radiological versus histological diagnosis in UIP and NSIP: survival implications

BACKGROUND

High resolution computed tomography (HRCT) has an important diagnostic role in idiopathic interstitial pneumonia (IIP). We hypothesised that the HRCT appearance would have an impact on survival in patients with IIP.

METHODS

HRCT scans from patients with histological usual interstitial pneumonia (UIP; n=73) or histological non-specific interstitial pneumonia (NSIP; n=23) were characterised as definite UIP, probable UIP, indeterminate, probable NSIP, or definite NSIP. Cox regression analysis examined the relationships between histopathological and radiological diagnoses and mortality, controlling for patient age, sex, and smoking status.

RESULTS

All 27 patients with definite or probable UIP on HRCT had histological UIP; 18 of 44 patients with probable or definite NSIP on HRCT had histological NSIP. Patients with HRCT diagnosed definite or probable UIP had a shorter survival than those with indeterminate CT (hazards ratio (HR) 2.43, 95% CI 1.06 to 5.58; median survival 2.08 v 5.76 years) or HRCT diagnosed definite or probable NSIP (HR 3.47, 95% CI 1.58 to 7.63; median survival 2.08 v 5.81 years). Patients with histological UIP with no HRCT diagnosis of probable or definite UIP fared better than patients with histological UIP and an HRCT diagnosis of definite or probable UIP (HR 0.49, 95% CI 0.25 to 0.98; median survival 5.76 v 2.08 years) and worse than those with a histological diagnosis of NSIP (HR 5.42, 95% CI 1.25 to 23.5; median survival 5.76 v >9 years).

CONCLUSIONS

Patients with a typical HRCT appearance of UIP experience the highest mortality. A surgical lung biopsy is indicated for patients without an HRCT appearance of UIP to differentiate between histological UIP and NSIP.

Aging and panicogenic response to cholecystokinin tetrapeptide: an examination of the cholecystokinin system

Older age is associated with diminished symptomatic and cardiovascular response to the panicogenic agent cholecystokinin tetrapeptide (CCK-4). We hypothesized that circulating concentrations of endogenous CCK-4 and/or CCK-8 are increased in later life, possibly due to decreased enzymatic degradation, and that this is associated with desensitization of CCK-B receptors. The study group consisted of 20 healthy subjects aged 18-30 years and 20 healthy subjects aged 65-85 years. The two groups were compared on fasting basal plasma concentrations of CCK-4, sulfated CCK-8 (CCK-8s) and nonsulfated CCK-8 (CCK-8 ns), and on binding capacity of lymphocyte CCK-B receptors. Under single-blind (to subject) conditions, subjects were then administered an intravenous bolus of placebo, followed 50 min later by an intravenous bolus of 50 micro g of CCK-4. Plasma concentrations of total CCK (CCK(T)) were measured 2 min before and 2, 5, 10, and 15 min after each injection. Compared with younger subjects, older subjects had a significantly higher basal plasma concentration of CCK-8s and significantly diminished binding capacity of CCK-B receptors. Following injection of placebo, plasma CCK(T) concentrations did not significantly change from baseline in either age group, but the elderly had significantly higher concentrations than the young at 2, 5, and 10 min. Following injection of CCK-4, the plasma concentration of CCK(T) was highest at 2 min and declined after that. The elderly had significantly higher CCK(T) concentrations (ie. a slower decline in CCK(T)) than the young at 5, 10, and 15 min. These findings are consistent with our hypothesis and suggest that age-related changes in the CCK system could contribute to the diminished panicogenic response to exogenous CCK-4 in older persons.

Clinical significance of histological classification of idiopathic interstitial pneumonia

Patients with idiopathic interstitial pneumonias (IIPs) can be subdivided into groups based on the histological appearance of lung tissue obtained by surgical biopsy. The quantitative impact of histological diagnosis, baseline factors and response to therapy on survival has not been evaluated. Surgical lung biopsy specimens from 168 patients with suspected IIP were reviewed according to the latest diagnostic criteria. The impact of baseline clinical, physiological, radiographic and histological features on survival was evaluated using Cox regression analysis. The predictive value of honeycombing on high-resolution computed tomography (HRCT) as a surrogate marker for usual interstitial pneumonia (UIP) was examined. The response to therapy and survival of 39 patients treated prospectively with high-dose prednisone was evaluated. The presence of UIP was the most important factor influencing mortality. The risk ratio of mortality when UIP was present was 28.46 (95% confidence interval (CI) 5.5-148.0; p=0.0001) after controlling for patient age, duration of symptoms, radiographic appearance, pulmonary physiology, smoking history and sex. Honeycombing on HRCT indicated the presence of UIP with a sensitivity of 90% and specificity of 86%. Patients with nonspecific interstitial pneumonia were more likely to respond or remain stable (9 of 10) compared to patients with UIP (14 of 29) after treatment with prednisone. Patients remaining stable had the best prognosis. The risk ratio of mortality for stable patients compared to nonresponders was 0.32 (95% CI 0.11-0.93; p=0.04) in all patients and 0.33 (95% CI 0.12-0.96; p=0.04) in patients with UIP. The histological diagnosis of usual interstitial pneumonia is the most important factor determining survival in patients with suspected idiopathic interstitial pneumonia. The presence of honeycombing on high-resolution computed tomography is a good surrogate for usual interstitial pneumonia and could be utilized in patients unable to undergo surgical lung biopsy. Patients with nonspecific interstitial pneumonia are more likely to respond or remain stable following a course of prednisone. Patients remaining stable following prednisone therapy have the best prognosis.