Grey matter volume predicts improvement in geriatric depression in response to Tai Chi compared to Health Education

OBJECTIVES

Geriatric depression (GD) is associated with cognitive impairment and brain atrophy. Tai-Chi-Chih (TCC) is a promising adjunct treatment to antidepressants. We previously found beneficial effects of TCC on resting state connectivity in GD. We now tested the effect of TCC on gray matter volume (GMV) change and the association between baseline GMV and clinical outcome.

PARTICIPANTS

Forty-nine participants with GD (>=60 y) underwent antidepressant treatment (38 women).

INTERVENTION

Participants completed 3 months of TCC (N = 26) or health and wellness education control (HEW; N = 23).

MEASUREMENTS

Depression and anxiety symptoms and MRI scans were acquired at baseline and 3-month follow-up. General linear models (GLMs) tested group-by-time interactions on clinical scores. Freesurfer 6.0 was used to process T1-weighted images and to perform voxel-wise whole-brain GLMs of group on symmetrized percent GMV change, and on the baseline GMV and symptom change association, controlling for baseline symptom severity. Age and sex served as covariates in all models.

RESULTS

There were no group differences in baseline demographics or clinical scores, symptom change from baseline to follow-up, or treatment-related GMV change. However, whole-brain analysis revealed that lower baseline GMV in several clusters in the TCC, but not the HEW group, was associated with larger improvements in anxiety. This was similar for right precuneus GMV and depressive symptoms.

CONCLUSIONS

While we observed no effect on GMV due to the interventions, baseline regional GMV predicted symptom improvements with TCC but not HEW. Longer trials are needed to investigate the long-term effects of TCC on clinical symptoms and neuroplasticity.

Mediating role of obesity on the association between disadvantaged neighborhoods and intracortical myelination

We investigated the relationship between neighborhood disadvantage (area deprivation index [ADI]) and intracortical myelination (T1-weighted/T2-weighted ratio at deep to superficial cortical levels), and the potential mediating role of the body mass index (BMI) and perceived stress in 92 adults. Worse ADI was correlated with increased BMI and perceived stress (p's<.05). Non-rotated partial least squares analysis revealed associations between worse ADI and decreased myelination in middle/deep cortex in supramarginal, temporal, and primary motor regions and increased myelination in superficial cortex in medial prefrontal and cingulate regions (p<.001); thus, neighborhood disadvantage may influence the flexibility of information processing involved in reward, emotion regulation, and cognition. Structural equation modelling revealed increased BMI as partially mediating the relationship between worse ADI and observed myelination increases (p=.02). Further, trans-fatty acid intake was correlated with observed myelination increases (p=.03), suggesting the importance of dietary quality. These data further suggest ramifications of neighborhood disadvantage on brain health.

Sex-specific brain microstructural reorganization in irritable bowel syndrome

ABSTRACT

Preliminary evidence suggests that there are sex differences in microstructural brain organization among individuals with irritable bowel syndrome (IBS). The aim of this study was to further investigate sex-dependent differences in brain microstructure and organization in a large sample of well-phenotyped participants with IBS compared with healthy controls. We hypothesized that female patients with IBS would show evidence for increased axonal strength and myelination within and between brain regions concerned with pain and sensory processing, when compared with males with IBS. We also hypothesized that female compared with male IBS subjects show greater levels of somatic awareness and sensory sensitivity consistent with multisystem sensory sensitivity. Diffusion tensor images and clinical assessments were obtained in 100 healthy controls (61 females) and 152 IBS (107 females) on a 3T Siemens Trio. Whole brain voxel-wise differences in fractional anisotropy, mean, radial and axial diffusivity, and track density as differences in somatic awareness and sensory sensitivity were assessed using the general linear model. Female compared with male IBS participants showed extensive microstructural alterations in sensorimotor, corticothalamic, and basal ganglia circuits involved in pain processing and integration of sensorimotor information. Together with the observed increases in symptom severity, somatic awareness, and sensory sensitivity, the findings support the hypotheses that the etiology and maintenance of symptoms in females with IBS may be driven by greater central sensitivity for multiple sensory stimuli.

Yoga Prevents Gray Matter Atrophy in Women at Risk for Alzheimer's Disease: A Randomized Controlled Trial

BACKGROUND

Female sex, subjective cognitive decline (SCD), and cardiovascular risk factors (CVRFs) are known risk factors for developing Alzheimer's disease (AD). We previously demonstrated that yoga improved depression, resilience, memory and executive functions, increased hippocampal choline concentrations, and modulated brain connectivity in older adults with mild cognitive impairment.

OBJECTIVE

In this study (NCT03503669), we investigated brain gray matter volume (GMV) changes in older women with SCD and CVRFs following three months of yoga compared to memory enhancement training (MET).

METHODS

Eleven women (mean age = 61.45, SD = 6.58) with CVRF and SCD completed twelve weeks of Kundalini Yoga and Kirtan Kriya (KY + KK) while eleven women (mean age = 64.55, SD = 6.41) underwent MET. Anxiety, resilience, stress, and depression were assessed at baseline and 12 weeks, as were T1-weighted MRI scans (Siemens 3T Prisma scanner). We used Freesurfer 6.0 and tested group differences in GMV change, applying Monte-Carlo simulations with alpha = 0.05. Region-of-interest analysis was performed for hippocampus and amygdala.

RESULTS

Compared to KY + KK, MET showed reductions in GMV in left prefrontal, pre- and post-central, supramarginal, superior temporal and pericalcarine cortices, right paracentral, postcentral, superior and inferior parietal cortices, the banks of the superior temporal sulcus, and the pars opercularis. Right hippocampal volume increased after yoga but did not survive corrections.

CONCLUSION

Yoga training may offer neuroprotective effects compared to MET in preventing neurodegenerative changes and cognitive decline, even over short time intervals. Future analyses will address changes in functional connectivity in both groups.

A Randomized Controlled Trial of Tai Chi Chih or Health Education for Geriatric Depression

OBJECTIVES

Geriatric depression is difficult to treat and frequently accompanied by treatment resistance, suicidal ideations and polypharmacy. New adjunctive mind-body treatment strategies can improve clinical outcomes in geriatric depression and reduce risk for side-effects of pharmacological treatments.

METHODS

We conducted a 3-month randomized controlled trial to assess the efficacy and tolerability of combining Tai Chi Chih (TCC) or Health Education and Wellness training (HEW) with the stable standard antidepressant treatment on mood and cognitive functioning in depressed older adults (NCT02460666). Primary outcome was change in depression as assessed by the Hamilton Rating Scale for Depression (HAM-D) post-treatment. Remission was defined as HAM-D ≤ 6; naturalistic follow-up continued for 6 months. We also assessed psychological resilience, health-related quality of life and cognition.

RESULTS

Of the 178 randomized participants, 125 completed the 3-month assessment and 117 completed the 6-month assessment. Dropout and tolerability did not differ between groups. Remission rate within TCC was 35.5% and 33.3%, compared to 27.0% and 45.8% in HEW, at 3 and 6 months respectively (χ²(1) = 1.0, p = 0.3; χ²(1) = 1.9, p =0.2). Both groups improved significantly on the HAM-D at 3 and 6 months. TCC demonstrated a greater improvement in general health compared to HEW.

CONCLUSIONS

Both TCC and HEW combined with a standard antidepressant treatment improved symptoms of depression in older adults. While TCC was superior to HEW in improving general health, we did not find group differences in improvement in mood and cognition.

Gut Microbiome Diversity and Abundance Correlate with Gray Matter Volume (GMV) in Older Adults with Depression

Growing evidence supports the concept that bidirectional brain–gut microbiome interactions play an important mechanistic role in aging, as well as in various neuropsychiatric conditions including depression. Gray matter volume (GMV) deficits in limbic regions are widely observed in geriatric depression (GD). We therefore aimed to explore correlations between gut microbial measures and GMV within these regions in GD. Sixteen older adults (>60 years) with GD (37.5% female; mean age, 70.6 (SD = 5.7) years) were included in the study and underwent high-resolution T1-weighted structural MRI scanning and stool sample collection. GMV was extracted from bilateral regions of interest (ROI: hippocampus, amygdala, nucleus accumbens) and a control region (pericalcarine). Fecal microbiota composition and diversity were assessed by 16S ribosomal RNA gene sequencing. There were significant positive associations between alpha diversity measures and GMV in both hippocampus and nucleus accumbens. Additionally, significant positive associations were present between hippocampal GMV and the abundance of genera Family_XIII_AD3011_group, unclassified Ruminococcaceae, and Oscillibacter, as well as between amygdala GMV and the genera Lachnospiraceae_NK4A136_group and Oscillibacter. Gut microbiome may reflect brain health in geriatric depression. Future studies with larger samples and the experimental manipulation of gut microbiome may clarify the relationship between microbiome measures and neuroplasticity.

The Role of Resilience in Irritable Bowel Syndrome, Other Chronic Gastrointestinal Conditions, and the General Population

BACKGROUND & AIMS

Resilience is the ability to adapt positively to stress and adversity. It is a potential therapeutic target as it is reduced in irritable bowel syndrome (IBS) compared to healthy controls and associated with worse symptom severity and poorer quality of life. The aim of this study was to examine if these findings are generalizable by comparing resilience between IBS versus the general population and other chronic gastrointestinal (GI) conditions.

METHODS

Participants in the general population completed an online survey containing questionnaires measuring demographics, diagnosis of IBS and other GI conditions, symptom severity, psychological symptoms, resilience, and early adverse life events (EALs). IBS was defined as having a physician diagnosis of IBS and/or meeting Rome criteria without co-morbid GI disease. All others were included in the general population group. The chronic GI conditions group included those with inflammatory bowel disease, celiac disease and/or microscopic colitis.

RESULTS

Resilience was lower in IBS (n = 820) than the general population (n = 1026; p < 0.001) and associated with worse IBS symptom severity (p < 0.05). Global mental health affected resilience differently in IBS compared to the general population (all p's < 0.05). EALs were associated with decreased ability to bounce back from adversity in both IBS and the general population (p < 0.001). Resilience scores were similar in IBS and other chronic GI conditions that present with similar symptoms.

CONCLUSIONS

Resilience is lower compared to the general U.S. population but does not appear to be specific to IBS as it is comparable to other chronic GI conditions. Low resilience negatively affects symptom severity and mental health and thus, may serve as a novel therapeutic target.

Sex Differences and Commonalities in the Impact of a Palatable Meal on Thalamic and Insular Connectivity

The neural mechanisms underlying subjective responses to meal ingestion remain incompletely understood. We previously showed in healthy men an increase in thalamocortical, and a decrease in insular-cortical connectivity in response to a palatable meal. As sex is increasingly recognized as an important biological variable, we aimed to evaluate sex differences and commonalities in the impact of a well-liked meal on thalamic and anterior insular connectivity in healthy individuals. Participants (20 women and 20 age-matched men) underwent resting-state magnetic resonance imaging (rsMRI) before and after ingesting a palatable meal. In general, the insula showed extensive postprandial reductions in connectivity with sensorimotor and prefrontal cortices, while the thalamus showed increases in connectivity with insular, frontal, and occipital cortices, in both women and men. However, reductions in insular connectivity were more prominent in men, and were related to changes in meal-related sensations (satiety and digestive well-being) in men only. In contrast, increases in thalamic connectivity were more prominent in women, and were related to changes in satiety and digestive well-being in women only. These results suggest that brain imaging may provide objective and sex-specific biomarkers of the subjective feelings associated with meal ingestion.

Quantifying Target Occupancy of Small Molecules Within Living Cells

The binding affinity and kinetics of target engagement are fundamental to establishing structure-activity relationships (SARs) for prospective therapeutic agents. Enhancing these binding parameters for operative targets, while minimizing binding to off-target sites, can translate to improved drug efficacy and a widened therapeutic window. Compound activity is typically assessed through modulation of an observed phenotype in cultured cells. Quantifying the corresponding binding properties under common cellular conditions can provide more meaningful interpretation of the cellular SAR analysis. Consequently, methods for assessing drug binding in living cells have advanced and are now integral to medicinal chemistry workflows. In this review, we survey key technological advancements that support quantitative assessments of target occupancy in cultured cells, emphasizing generalizable methodologies able to deliver analytical precision that heretofore required reductionist biochemical approaches.

Cortical thickness increases with levomilnacipran treatment in a pilot randomised double-blind placebo-controlled trial in late-life depression

BACKGROUND

Late-life depression (LLD) is associated with significant medical comorbidity, cognitive impairment, and suboptimal treatment response compared to depression experienced earlier in life. Levomilnacipran (LVM) is a novel antidepressant the effects of which on neuroplasticity have not yet been investigated. We investigated the effect of LVM on cortical thickness in a pilot randomised placebo-controlled trial in LLD.

METHODS

Twenty-nine adults (≥ 60 years) with major depression (48.3% female; mean age = 71.5 ± 5.8 years; mean education = 16.0 ± 1.7 years) were randomised to either LVM or placebo for 12 weeks. T1-weighted images were acquired at baseline and 12 weeks. Thirteen subjects (six LVM and seven placebo) completed the study. Group differences in cortical thickness change across the study period were evaluated, with age and total intracranial volume included as covariates.

RESULTS

Dropout rates did not differ significantly between groups. The LVM group had significantly more side effects, but no serious adverse events were reported. Lower LVM dose (≤ 40 mg) was better tolerated than higher doses (80-120 mg). Additionally, the LVM group showed a larger increase in cortical thickness in the right postcentral gyrus (primary somatosensory), supramarginal gyrus (sensory association region), and lateral occipital cortex (visual cortex) compared to the placebo group and greater reductions in the left insula.

CONCLUSIONS

LVM may be less tolerable by older adults with depression and the effects on cortical thickness across sensory and sensory association regions may be related to the experience of side effects. Larger studies are necessary to evaluate treatment efficacy, tolerability, and neural effects of LVM in LLD.

Role of brain imaging in disorders of brain-gut interaction: a Rome Working Team Report

Imaging of the living human brain is a powerful tool to probe the interactions between brain, gut and microbiome in health and in disorders of brain-gut interactions, in particular IBS. While altered signals from the viscera contribute to clinical symptoms, the brain integrates these interoceptive signals with emotional, cognitive and memory related inputs in a non-linear fashion to produce symptoms. Tremendous progress has occurred in the development of new imaging techniques that look at structural, functional and metabolic properties of brain regions and networks. Standardisation in image acquisition and advances in computational approaches has made it possible to study large data sets of imaging studies, identify network properties and integrate them with non-imaging data. These approaches are beginning to generate brain signatures in IBS that share some features with those obtained in other often overlapping chronic pain disorders such as urological pelvic pain syndromes and vulvodynia, suggesting shared mechanisms. Despite this progress, the identification of preclinical vulnerability factors and outcome predictors has been slow. To overcome current obstacles, the creation of consortia and the generation of standardised multisite repositories for brain imaging and metadata from multisite studies are required.

Anxiety symptoms are associated with smaller insular and orbitofrontal cortex volumes in late-life depression

BACKGROUND

Increasing understanding of the neural correlates of anxiety symptoms in late-life depression (LLD) could inform the development of more targeted and effective treatments.

METHODS

Grey matter volume (GMV) was assessed with volumetric magnetic resonance imaging in a sample of 113 adults ≥60 years with MDD using the following regions of interest: amygdala, anterior cingulate cortex (ACC), insula, orbitofrontal cortex (OFC), and temporal cortex.

RESULTS

After controlling for demographic (age, sex, education) and clinical variables (antidepressant use, anxiolytic use, duration of illness, medical comorbidity, cognitive functioning), greater severity of anxiety symptoms was associated with lower GMV bilaterally in the insula, F(1,102) = 6.63, p = 0.01, and OFC, F(1,102) = 8.35, p = 0.005. By contrast, depressive symptom severity was significantly associated with lower bilateral insula volumes, F(1,102) = 6.43, p = 0.01, but not OFC volumes, F(1,102) = 5.37, p = 0.02.

LIMITATIONS

Limitations include (1) the relatively mild nature of anxiety symptoms in our sample; (2) the cross-sectional research design, which prohibits inferences of directionality; (3) the relatively homogenous demographic of the sample, and (4) the exclusion of participants with significant psychiatric comorbidity, suicidality, or cognitive impairment.

CONCLUSIONS

Decreased OFC volumes may serve as a unique biomarker of anxiety symptoms in LLD. Future longitudinal and clinical studies with long-term follow up and more diverse samples will help further elucidate the biological, psychological, and social factors affecting associations between anxiety and brain morphology in LLD.

Resilience is decreased in irritable bowel syndrome and associated with symptoms and cortisol response

BACKGROUND

Irritable bowel syndrome (IBS) is a stress-sensitive disorder associated with early adverse life events (EALs) and a dysregulated hypothalamic-pituitary-adrenal (HPA) axis. Resilience is the ability to recover and adapt positively to stress but has not been well studied in IBS. The aims of this study are to compare resilience in IBS and healthy controls (HCs) and to assess its relationships with IBS symptom severity, quality of life (QOL), EALs, and HPA axis response.

METHODS

Two hundred fifty-six subjects (154 IBS, 102 HCs) completed questionnaires for resilience (Connor-Davidson Resilience Scale [CD-RISC] and Brief Resilience Scale [BRS]), IBS symptoms, IBS-QOL, and EALs. Ninety-six of these subjects had serial serum adrenocorticotropic hormone (ACTH) and cortisol levels to exogenous corticotrophin-releasing hormone (CRH) and ACTH measured. The relationship between IBS status, resilience, and other variables of interest was assessed by regression analysis after adjusting for demographics and neuroticism, a predictor of resilience.

KEY RESULTS

Resilience was significantly lower in IBS compared to HCs (CD-RISC: 72.16±14.97 vs 77.32±12.73, P=.003; BRS: 3.29±0.87 vs 3.93±0.69, P<.001); however, only BRS was significant after controlling for neuroticism (P=.001). Lower BRS scores were associated with greater IBS symptom severity (P=.002), poorer IBS-QOL (P<.001), and a higher number of EALs (P=.01). There was a significant interaction between BRS resilience and IBS status for ACTH-stimulated cortisol response (P=.031); more resilient IBS subjects had lower cortisol response, and more resilient HCs had higher cortisol response.

CONCLUSIONS AND INFERENCES

Lower resilience is associated with IBS status, worse IBS symptom severity, lower IBS-QOL, greater EALs, and stress hyperresponsiveness.

Brain networks associated with cognitive and hedonic responses to a meal

BACKGROUND

We recently reported interrelated digestive, cognitive, and hedonic responses to a meal. The aim of this study was to identify brain networks related to the hedonic response to eating.

METHODS

Thirty-eight healthy subjects (20-38 age range) were evaluated after a 5-hour fast and after ingestion of a test meal (juice and warm ham and cheese sandwich, 300 mL, 425 kcal). Perceptual and affective responses (satiety, abdominal fullness, digestive well-being, and positive mood), and resting scans of the brain using functional MRI (3T Trio, Siemens, Germany) were evaluated immediately before and after the test meal. A high-order group independent component analysis was performed to investigate ingestion-related changes in the intrinsic connectivity of brain networks, with a focus on thalamic and insular networks.

KEY RESULTS

Ingestion induced satiation (3.3±0.4 score increase; P<.001) and abdominal fullness (2.4±0.3 score increase; P<.001). These sensations included an affective dimension involving digestive well-being (2.8±0.3 score increase; P<.001) and positive mood (1.8±0.2 score increase; P<.001). In general, thalamo-cortical connectivity increased with meal ingestion while insular-cortical connectivity mainly decreased. Furthermore, larger meal-induced changes (increase/decrease) in specific thalamic connections were associated with smaller changes in satiety/fullness. In contrast, a larger meal-induced decrease in insular-anterior cingulate cortex connectivity was associated with increased satiety, fullness, and digestive well-being.

CONCLUSIONS AND INFERENCES

Perceptual and emotional responses to food intake are related to brain connectivity in defined functional networks. Brain imaging may provide objective biomarkers of subjective effects of meal ingestion.

Improvements in well-being and vagal tone following a yogic breathing-based life skills workshop in young adults: Two open-trial pilot studies

Background:

While efficacy of Sudarshan Kriya Yoga (SKY) has been demonstrated in a number of prior studies, little is known about the effects of SKY taught as part of the Your Enlightened Side (YES+) workshop designed for college students and other young adults.

Aims:

This study aimed to assess the effects of YES+, a yogic breathing-based life skills workshop, on multiple measures of well-being and physiological stress response.

Materials and Methods:

Two nonrandomized open-trial pilot studies were conducted with a total of 74 young adults (age 25.4 ± 6.6 years; 55% female). Study 1 collected a variety of self-report questionnaires at baseline, postworkshop, and 1-month follow-up. Study 2 collected self-report questionnaires in addition to electrocardiography with a stationary cycling challenge at baseline and 1-month follow-up.

Results:

Study 1: Improvements in self-reported depression (P's ≤ 0.010), perceived stress (P's ≤ 0.002), life satisfaction (P's ≤ 0.002), social connectedness (P's ≤ 0.004), and gratitude (P's ≤ 0.090) were observed at postworkshop and 1-month after workshop relative to baseline. Study 2: Improvements in self-reported emotion regulation were observed at 1-month follow-up relative to baseline (P = 0.019). Positive and Negative Affect Schedule-Expanded Form positive affect increased (P = 0.021), while fatigue and sadness decreased (P's ≤ 0.005). During the stationary cycling challenge, rate to recovery of electrocardiography inter-beat interval also increased from baseline to 1-month follow-up (P = 0.077).

Conclusions:

These findings suggest that a life skills workshop integrating yogic breathing techniques may provide self-empowering tools for enhancing well-being in young adults. Future research is indicated to further explore these effects, particularly in regards to vagal tone and other aspects of stress physiology.

Pain and Interoception Imaging Network (PAIN): A multimodal, multisite, brain-imaging repository for chronic somatic and visceral pain disorders

The Pain and Interoception Imaging Network (PAIN) repository (painrepository.org) is a newly created NIH (NIDA/NCCAM) funded neuroimaging data repository that aims to accelerate scientific discovery regarding brain mechanisms in pain and to provide more rapid benefits to pain patients through the harmonization of efforts and data sharing. The PAIN Repository consists of two components, an Archived Repository and a Standardized Repository. Similar to other 'open' imaging repositories, neuroimaging researchers can deposit any dataset of chronic pain patients and healthy controls into the Archived Repository. Scans in the Archived Repository can be very diverse in terms of scanning procedures and clinical metadata, complicating the merging of datasets for analyses. The Standardized Repository overcomes these limitations through the use of standardized scanning protocols along with a standardized set of clinical metadata, allowing an unprecedented ability to perform pooled analyses. The Archived Repository currently includes 741 scans and is rapidly growing. The Standardized Repository currently includes 433 scans. Pain conditions currently represented in the PAIN repository include: irritable bowel syndrome, vulvodynia, migraine, chronic back pain, and inflammatory bowel disease. Both the PAIN Archived and Standardized Repositories promise to be important resources in the field of chronic pain research. The enhanced ability of the Standardized Repository to combine imaging, clinical and other biological datasets from multiple sites in particular make it a unique resource for significant scientific discoveries.

Sex differences in emotion-related cognitive processes in irritable bowel syndrome and healthy control subjects

Greater responsiveness of emotional arousal circuits in relation to delivered visceral pain has been implicated as underlying central pain amplification in irritable bowel syndrome (IBS), with female subjects showing greater responses than male subjects. Functional magnetic resonance imaging was used to measure neural responses to an emotion recognition paradigm, using faces expressing negative emotions (fear and anger). Sex and disease differences in the connectivity of affective and modulatory cortical circuits were studied in 47 IBS (27 premenopausal female subjects) and 67 healthy control subjects (HCs; 38 premenopausal female subjects). Male subjects (IBS+HC) showed greater overall brain responses to stimuli than female subjects in prefrontal cortex, insula, and amygdala. Effective connectivity analyses identified major sex- and disease-related differences in the functioning of brain networks related to prefrontal regions, cingulate, insula, and amygdala. Male subjects had stronger connectivity between anterior cingulate subregions, amygdala, and insula, whereas female subjects had stronger connectivity to and from the prefrontal modulatory regions (medial/dorsolateral cortex). Male IBS subjects demonstrate greater engagement of cortical and affect-related brain circuitry compared to male control subjects and female subjects, when viewing faces depicting emotions previously shown to elicit greater behavioral and brain responses in male subjects.

Increased startle responses in interstitial cystitis: evidence for central hyperresponsiveness to visceral related threat

PURPOSE

Hypersensitivity to visceral stimuli in interstitial cystitis/painful bladder syndrome may result from enhanced responsiveness of affective circuits (including the amygdala complex) and associated central pain amplification. Potentiation of the eyeblink startle reflex under threat is mediated by output from the amygdala complex and, therefore, represents a noninvasive marker to study group differences in responsiveness in this brain circuit.

MATERIALS AND METHODS

Acoustic startle responses were examined in female patients with interstitial cystitis/painful bladder syndrome (13) and healthy controls (16) during context threat (application of muscle stimulation electrodes to the lower abdomen overlying the bladder), and cued conditions for safety (no stimulation possible), anticipation and imminent threat of aversive abdominal stimulation over the bladder.

RESULTS

Patients showed significantly greater startle responses during nonimminent threat conditions (baseline, safe and anticipation periods) while both groups showed similar robust startle potentiation during the imminent threat condition. Higher rates of anxiety and depression symptoms in the patient group did not account for the group differences in startle reflex magnitude.

CONCLUSIONS

Compared to controls, female patients with interstitial cystitis/painful bladder syndrome showed increased activation of a defensive emotional circuit in the context of a threat of abdominal pain. This pattern is similar to that previously reported in patients with anxiety disorders as well as those with irritable bowel syndrome. Since these circuits have an important role in central pain amplification related to affective and cognitive processes, these results support the hypothesis that the observed abnormality may be involved in the enhanced perception of bladder signals associated with interstitial cystitis/painful bladder syndrome.

Studying the brain-gut axis with pharmacological imaging

Pharmacological imaging provides great potential both for evaluating the efficacy of new candidate compounds in the treatment of gastrointestinal symptom-based disorders, and for furthering our understanding of the underlying pathophysiology of such disorders. By combining evaluation of symptoms, behavior, and brain responses to relevant stimuli, use of neuroimaging is able to move the study of brain-gut disorders away from more subjective outcomes and emphasize the underlying neural networks involved in symptom generation and treatment. This chapter reviews the state of the art in pharmacological imaging studies, both in human subjects and in animal models of brain-gut interactions.

171. IDENTIFICATION OF DECIDUALISATION-INDUCED PROTEIN CHANGES IN HUMAN ENDOMETRIAL STROMAL CELLS BY PROTEOMICS

Decidualisation of human endometrial stromal cells (HESC) is pivotal for successful implantation and can be induced by cAMP analogues such as 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) and ligands to enhance cellular cAMP levels. The resulting decidualisation HESC is recognised by morphological changes and cellular products such as prolactin or insulin-like growth factors. The regulation of proteins during decidualisation HESC has yet to be clearly identified. The aim of this study was to identify proteins that are altered during decidualisation. HESC were isolated and decidualised with 500μM of 8-Br-cAMP for 72 hours. Decidualisation success was determined by prolactin assay. 2D differential in-gel electrophoresis (DIGE) was used to examine differentially expressed proteins between control and 8-Br-cAMP treated HESC. The proteins of interest were validated by Western blot and/or immunohistochemistry. A total of 88 differentially expressed proteins were identified by matrix assisted laser desorption/ionisation (MALDI) and/or liquid chromatography mass spectrometry (LC-MS). The proteins that were up regulated during decidualisation include insulin growth factor binding protein as well as caldesmon, tropomycin, actin, tubulin, SRC substrate cortactin and calponin-1 which contribute to the re-organisation of cell cytoskeletal restructuring and remodelling. Proteins associated with cellular growth and transformation such as annexin, nuclear migration factor protein and elongation factor 1B were also up regulated. These results suggest that the process of decidualisation is complicated requiring synergy and cross-talk between structural and cell growth proteins and pathways.

Dehydration versus deamination of N-terminal glutamine in collision-induced dissociation of protonated peptides

Some of the most prominent "neutral losses" in peptide ion fragmentation are the loss of ammonia and water from N-terminal glutamine. These processes are studied by electrospray ionization mass spectrometry in singly- and doubly-protonated peptide ions undergoing collision-induced dissociation in a triple quadrupole and in an ion trap instrument. For this study, four sets of peptides were synthesized: (1) QLLLPLLLK and similar peptides with K replaced by R, H, or L, and Q replaced by a number of amino acids, (2) QLnK (n = 0, 1, 3, 5, 7, 9, 11), (3) QLnR (n = 0, 1, 3, 5, 7, 9), and (4) QLn (n = 1, 2, 3, 4, 8). The results for QLLLPLLLK and QLLLPLLLR show that the singly protonated ions undergo loss of ammonia and to a smaller extent loss of water, whereas the doubly protonated ions undergo predominant loss of water. The fast fragmentation next to P (forming the y5 ion) occurs to a larger extent than the neutral losses from the singly protonated ions but much less than the water loss from the doubly protonated ions. The results from these and other peptides show that, in general, when N-terminal glutamine peptides have no "mobile protons", that is, the number of charges on the peptide is no greater than the number of basic amino acids (K, R, H), deamination is the predominant neutral loss fragmentation, but when mobile protons are present the predominant process is the loss of water. Both of these processes are faster than backbone fragmentation at the proline. These results are rationalized on the basis of resonance stabilization of the two types of five-membered ring products that would be formed in the neutral loss processes; the singly protonated ion yields the more stable neutral pyrrolidinone ring whereas the doubly protonated ion yields the protonated aminopyrroline ring (see Schemes). The generality of these trends is confirmed by analyzing an MS/MS spectra library of peptides derived from tryptic digests of yeast. In the absence of mobile protons, glutamine deamination is the most rapid neutral loss process. For peptides with mobile protons, dehydration from glutamine is far more rapid than from any other amino acid. Most strikingly, end terminal glutamine is by far the most labile source of neutral loss in excess-proton peptides, but not highly exceptional when mobile protons are not available. In addition, rates of deamination are faster in lysine versus arginine C-terminus peptides and 20 times faster in positively charged than negatively charged peptides, demonstrating that these formal neutral loss reactions are not "neutral reactions" but depend on charge state and stability.

240. Spatial and temporal expression pattern of furin in the human endometrium

Furin is a proprotein convertase (PC) implicated in the endoproteolytic maturation of inactive protein precursors of growth factors, hormones, receptors, and viral envelope glycoproteins.1 Two functionally active forms of furin, one membrane-bound containing a C-terminal transmembrane domain (TD) and a cytoplasmic tail (CT), and one soluble without the TD and CT, have been characterised. We have previously shown that PC6, one of the PCs closely related to furin, is expressed in the human endometrium and is closely associated with decidualization of stromal cells during implantation.2 Although furin is ubiquitously expressed, its expression in the human endometrium is unknown. In this study, we investigated the spatial and temporal expression pattern of furin in the human endometrium using RT-PCR and immunohistochemistry. While furin expression is detected throughout the menstrual cycle and during early pregnancy, lowest mRNA levels are seen during the proliferative phase. Using an antibody directed against the C-terminus of the membrane bound form, furin is detected in the stroma, glandular and luminal epithelium, as well as in endothelia and neutrophils throughout the menstrual cycle and during early pregnancy. In the stroma, highest levels of furin are present during menstruation (n = 3), they are also high during the proliferative phase (n = 4), but significantly lower levels are detected during the secretory phase (n = 10, P < 0.05, Tukey HSD). In the first trimester decidua, furin is present in well decidualised stromal cells. The overall expression pattern of furin is different to that of PC6; in particular, furin expression is associated only with well decidualized stromal cells whereas PC6 is involved in the initial stages of decidualization. These data suggest that furin and PC6 play different roles in the human endometrium, especially during embryo implantation. (1)Nakayama K. (1997). Biochem. J. 327, 625–635.(2)Nie et al. (2005). Biol. Reprod. 72, 1029–1036.

Sex-related hemispheric lateralization of amygdala function in emotionally influenced memory: an FMRI investigation

The amygdala appears necessary for enhanced long-term memory associated with emotionally arousing events. Recent brain imaging investigations support this view and indicate a sex-related hemispheric lateralization exists in the amygdala relationship to memory for emotional material. This study confirms and further explores this finding. Healthy men and women underwent functional Magnetic Resonance Imaging (fMRI) while viewing a series of standardized slides that were rated by the subjects as ranging from emotionally neutral to highly arousing. Two weeks later, memory for the slides was assessed in an incidental recognition test. The results demonstrate a significantly stronger relationship in men than in women between activity of the right hemisphere amygdala and memory for those slides judged as arousing, and a significantly stronger relationship in women than in men between activity of the left hemisphere amygdala and memory for arousing slides. An ANOVA confirmed a significant interaction between sex and hemisphere regarding amygdala function in memory. These results provide the strongest evidence to date of a sex-related hemispheric lateralization of amygdala function in memory for emotional material. Furthermore, they underscore the view that investigations of neural mechanisms underlying emotionally influenced memory must anticipate, and begin to account for, the apparently substantial influence of sex.

Amygdala modulation of parahippocampal and frontal regions during emotionally influenced memory storage

Considerable evidence from both animal and human subject research supports the hypothesis that the amygdala, when activated by emotional arousal, modulates memory storage processes in other brain regions. By this hypothesis, changes in the functional interactions of the amygdala with other brain regions during emotional conditions should underlie, at least in part, enhanced memory for emotional material. Here we examined the influence of the human amygdala on other brain regions under emotional and nonemotional learning conditions using structural equation modeling (SEqM). Eleven male subjects received two PET scans for regional cerebral glucose metabolism-one scan while viewing a series of emotionally provocative (negative) film clips and a second scan while viewing a series of more emotionally neutral film clips. Enhanced activity in the right amygdala was related to enhanced memory for the emotional films. To identify potential candidate voxels for SEqM, the functional connectivity of the maximally activated voxel within the right amygdala was investigated using partial least squares. A subset of regions identified by this analysis showing differences functional connectivity with the amygdala between the emotional versus neutral film conditions were then submitted to SEqM, which revealed significantly increased amygdala influences on the ipsilateral parahippocampal gyrus and ventrolateral prefrontal cortex during the emotional relative to the neutral film viewing condition. These findings support the view that increased influences from the amygdala, presumably reflecting its memory-modulation function, occur during emotionally arousing learning situations.

Modulation of memory consolidation for olfactory learning by reversible inactivation of the basolateral amygdala

The role of the basolateral amygdala (BLA) in the consolidation of an association between an olfactory stimulus and footshock was investigated with a reversible lesion technique of post-training intra-BLA infusions of tetrodotoxin. Rats receiving tetrodotoxin infusions following paired odor-shock presentations spent more time near the odor, and reacted differently on contact with the odor when tested 24 hr after training, than did rats receiving paired presentations and saline infusions, but they did not differ from rats receiving unpaired presentations and saline infusions. The results indicate that the BLA plays a similar role in influencing consolidation of olfactory-based memory as it does for memory based on other modalities. Thus, these findings strengthen the view that the BLA plays a general role in modulation of memory storage for emotionally arousing events.

Modulation of memory consolidation for olfactory learning by reversible inactivation of the basolateral amygdala

The role of the basolateral amygdala (BLA) in the consolidation of an association between an olfactory stimulus and footshock was investigated with a reversible lesion technique of post-training intra-BLA infusions of tetrodotoxin. Rats receiving tetrodotoxin infusions following paired odor-shock presentations spent more time near the odor, and reacted differently on contact with the odor when tested 24 hr after training, than did rats receiving paired presentations and saline infusions, but they did not differ from rats receiving unpaired presentations and saline infusions. The results indicate that the BLA plays a similar role in influencing consolidation of olfactory-based memory as it does for memory based on other modalities. Thus, these findings strengthen the view that the BLA plays a general role in modulation of memory storage for emotionally arousing events.

Recombinant human granulocyte colony-stimulating factor therapy for patients with neutropenia and/or neutrophil dysfunction secondary to glycogen storage disease type 1b

The purpose of this study was to evaluate the efficacy and toxicity of recombinant human granulocyte colony-stimulating factor (rhG-CSF) therapy in patients with neutropenia and/or neutrophil dysfunction secondary to glycogen storage disease (GSD) type 1b. Thirteen patients with neutropenia and/or neutrophil dysfunction secondary to GSD type 1b were treated with rhG-CSF. The effects of therapy on neutrophil numbers and in vitro neutrophil function and on bone marrow cellularity and morphology were studied. The clinical status of the patients and the occurrence of adverse events associated with rhG-CSF use were monitored. Use of rhG-CSF therapy was associated with a significant increase in circulating neutrophil numbers (P <. 01) and an improvement in neutrophil function as assessed in vitro. In addition, rhG-CSF therapy produced a significant increase in marrow cellularity and an increase in myeloid:erythroid (M:E) ratio, indicating stimulation of granulopoeisis. No adverse effects on marrow function were noted; in particular, no myelodysplasia or marrow exhaustion was seen. Use of rhG-CSF therapy was associated with objective and subjective improvements in infection-related morbidity. The therapy was well tolerated, although all patients developed splenomegaly, and 5 patients developed mild hypersplenism that did not require any specific treatment. rhG-CSF therapy is efficacious in the management of neutropenia and neutrophil dysfunction associated with GSD type 1b. Patients on this therapy need to be monitored for hypersplenism. Continued follow-up will be necessary to confirm long-term safety; however, no significant short-term toxicity was noted.

Sex-related difference in amygdala activity during emotionally influenced memory storage

We tested the possibility suggested by previous imaging studies that amygdala participation in the storage of emotionally influenced memory is differentially lateralized in men and women. Male and female subjects received two PET scans for regional cerebral glucose-one while viewing a series of emotionally provocative (negative) films, and a second while viewing a series of matched, but emotionally more neutral, films. Consistent with suggestions from several previously published studies, enhanced activity of the right, but not the left, amygdala in men was related to enhanced memory for the emotional films. Conversely, enhanced activity of the left, but not the right, amygdala in women was related to enhanced memory for the emotional films. These results demonstrate a clear gender-related lateralization of amygdala involvement in emotionally influenced memory, and indicate that theories of the neurobiology of emotionally influenced memory must begin to account for the influence of gender.

Decreased superoxide production, degranulation, tumor necrosis factor alpha secretion, and CD11b/CD18 receptor expression by adherent monocytes from preterm infants

Preterm infants have an increased incidence of infection, which is principally due to deficiencies in neonatal host defense mechanisms. Monocyte adherence is important in localizing cells at sites of infection and is associated with enhanced antimicrobial functions. We isolated cord blood monocytes from preterm and full-term infants to study their adhesion and immune functions, including superoxide (O2-) generation, degranulation, and cytokine secretion and their adhesion receptors. O2- production and degranulation were significantly diminished, by 28 and 37%, respectively, in adherent monocytes from preterm infants compared to full-term infants (P < 0. 05); however, these differences were not seen in freshly isolated cells. We also observed a significant decrease of 35% in tumor necrosis factor alpha secretion by lipopolysaccharide-stimulated adherent monocytes from preterm infants compared to full-term infants (P < 0.05); however, this difference was not observed in interleukin-1beta or interleukin-6 production by the monocytes. The cell surface expression of the CD11b/CD18 adhesion receptor subunits was significantly decreased (by 60 and 52%, respectively) in monocytes from preterm infants compared to full-term infants (P < 0. 01). The cascade of the immune response to infection involves monocyte upregulation and adherence via CD11b/CD18 receptors followed by cell activation and the release of cytokines and bactericidal products. We speculate that monocyte adherence factors may be important in the modulation of immune responses in preterm infants.

Inhibition of human neutrophil beta2-integrin-dependent adherence by hyperbaric O2

Animal and clinical investigations have reported that exposure to hyperbaric O(2) improved the outcome of some reperfusion injuries. Animal studies have suggested that this may be due to an inhibition of leukocyte adherence to injured endothelium. This investigation tested the hypothesis that exposure to hyperbaric O(2) would inhibit beta2-integrin-dependent adherence of human neutrophils. Subjects were exposed to O(2) at partial pressures of up to 3 atmospheres absolute (ATA; 1 ATA = 0.1 MPa) for 45 min, and neutrophil binding to nylon columns and to fibrinogen-coated surfaces was measured. Exposure to O(2) at 2.8 or 3.0 ATA inhibited beta2-integrin-dependent neutrophil adherence but had no effect on the cell-surface expression of beta2-integrins, respiratory burst in response to phorbol ester, or non-beta2-integrin-dependent adherence to plastic plates coated with a fibronectin-like protein. beta2-Integrin adherence was restored by incubating blood with 8-bromoguanosine 3',5'-cyclic monophosphate (cGMP) and hyperbaric O(2) inhibited synthesis of cGMP by neutrophils stimulated with N-formyl-Met-Leu-Phe (FMLP). In studies of cell fractions, the activity of membrane guanylate cyclase was found to be increased by incubation with FMLP as well as by atrial natriuretic peptide (ANP) plus ATP. Hyperbaric O(2) had no effect on the basal activity of soluble or membrane-bound guanylate cyclase. However, hyperbaric O(2) inhibited the function of both the extracellular binding domain of membrane guanylate cyclase as well as intracellular catalytic activity. There are approximately 7,300 membrane guanylate cyclase molecules per cell, based on binding studies with ANP, with a dissociation constant of approximately 450 pM. Hyperbaric O(2) inhibits the function of human neutrophil beta2-integrins by a process linked to impaired synthesis of cGMP.

Production of T-helper cell subsets and cytokines by lymphocytes from patients with chronic mucocutaneous candidiasis

Chronic mucocutaneous candidiasis (CMC) is a heterogeneous group of disorders characterized by recurrent and persistent superficial candidal infections. Cytokine-induced dysregulation of T-helper cell function has been described in other immune-deficient states but has not been studied in CMC patients. We studied T-helper cell subsets by flow cytometry and cytokine production by stimulated lymphocytes in six CMC patients, two healthy pediatric controls, and five healthy adult controls. Peripheral blood lymphocytes were stimulated in vitro with phytohemagglutinin or Candida albicans extract, and the production of interleukin-2R (IL-2R), IL-4, IL-10, and gamma interferon in the supernatants was measured by enzyme-linked immunosorbent assay. CMC patients had a decrease in the CD29+/CD29+ cell population compared with the numbers in controls (P < 0.02). The percentage of CD4+/CD45RA+ cells was greater in patients than in controls, but the difference was not significant. There was no difference in the production of IL-10 or gamma interferon by the patient lymphocytes. CMC patients produced more IL-4 than the controls (P < 0.001), whereas the controls tended to produce more IL-2R than the patients (P = 0.19). These findings support the concept that a decrease in CD4+/CD29+ T-helper inducer cells along with T-helper cell dysregulation may lead to defective memory responses to antigens in CMC patients and a decrease in cell-mediated immunity due to inhibition of TH1 cells by increased levels of IL-4.

Fibrous matrix of ventricular myocardium in tricuspid atresia compared with normal heart. A quantitative analysis

BACKGROUND

The collagen matrix is a small component of the myocardium, but it provides a supportive framework. An increase in collagen in the pressure-overloaded ventricle is known to cause myocardial stiffness. However, little is known about the collagen matrix in the volume-overloaded ventricle, particularly in relation to congenital heart disease.

METHODS AND RESULTS

We examined a total of 53 hearts with tricuspid atresia and 58 normal hearts matched for age. Using a microscopic-morphometric method, we analyzed the percentage per field area occupied by interstitial fibrous tissue in four sites in the ventricular mass for each specimen. A comparison of sampling sites showed no significant variations between normal and malformed hearts. Results from a homogeneity of regression co-efficients analysis suggested that the two groups shared the same basic relation of proportion of fibrosis with age. The use of ANCOVA, however, revealed a clear separation between the extents of fibrous tissue in the two groups of hearts.

CONCLUSIONS

The myocardium of hearts with tricuspid atresia is consistently more fibrotic than normal heart and is probably an inherent part of the malformation. This difference could explain, at least in part, the clinical observation that the left ventricle is frequently abnormal, even at an early age.

Cytokine elevations in infants with bacterial and aseptic meningitis

We sought to determine whether the detection of cytokines, produced during the inflammatory response, would aid in the diagnosis of meningitis in young infants. We measured cerebrospinal fluid (CSF) and plasma levels of interleukin-6 (IL-6) and tumor necrosis factor (TNF) in 62 infants less than 6 months of age whose condition was evaluated for meningitis. Twenty infants had culture-proved meningitis, 22 had aseptic meningitis, and 20 control infants had no evidence of meningitis. The CSF IL-6 levels were elevated in all 20 infants with bacterial meningitis and in 9 of 22 infants with aseptic meningitis but were undetectable in all control subjects. Furthermore, CSF IL-6 levels were 10 times greater in infants with bacterial versus aseptic meningitis (p < 0.001). Levels of TNF in CSF were detected in 12 of 20 infants with bacterial meningitis and were undetectable in infants with aseptic meningitis and in control infants (p < 0.02). Plasma IL-6 and TNF levels were unreliable for the detection of meningitis in this patient population. We conclude that the presence of IL-6 in the CSF reliably identifies infants with meningitis and that the presence of CSF TNF is a highly specific indicator of bacterial meningeal inflammation.

Resonance Raman spectroscopic characterization of the molybdopterin active site of DMSO reductase

Resonance Raman spectra are compared for Rhodobacter sphaeroides dimethyl sulfoxide reductase, an enzyme containing a molybdopterin cofactor, and two model compounds, I and II, which have pterin and quinoxaline, respectively, attached to a Cp2Mo[IV]-dithiolene chelate [Cp = cyclopentadienyl]. The effect of 34S incorporation was also determined. Several bands in the 200-500 cm-1 region show remarkably similar patterns of frequencies and isotope shifts between protein and models: a band at 351 cm-1 shifts 6-8 cm-1, and bands at lower and higher frequencies show smaller shifts upon 34S substitution. A normal coordinate analysis on II indicates the 351 cm-1 mode to be the symmetric Mo-S[dithiolene] stretch and the remaining low-frequency modes to contain contributions from deformations of the quinoxaline ring as well as from Mo-S stretching. The similarity in the low-frequency spectra between the model compounds and the enzyme strongly supports a dithiolene chelate as the mode of Mo-pterin interaction in the cofactor. Resonance enhancement of both high- and low-frequency quinoxaline or pterin modes is observed for both model compounds, implicating the heterocyclic rings as part of the electronic system involved in the Mo-dithiolene charge transfer transitions. RR spectra of 6-methylpterin and biopterin are reported and used to identify the pterin and quinoxaline high-frequency bands in the model compound spectra. The dithiolene C = C stretch is tentatively assigned to bands at 1506 cm-1 in I and 1515 cm-1 in II.(ABSTRACT TRUNCATED AT 250 WORDS)

Amrinone prevents muscle protein wasting during chronic sepsis

The time course for the effects of sepsis on rates of protein synthesis, RNA contents, and translational efficiencies was measured in mixed muscles of rat hindlimb perfused in vitro 3, 5, and 10 days after induction of sepsis. Furthermore, the effect of daily injections of amrinone (5 mg.kg-1.day-1) on muscle protein synthesis was investigated. On day 3 of sepsis, decreased rates of protein synthesis in muscle from untreated septic animals or septic rats treated with amrinone resulted from a reduced food intake. When food intake became normalized to control after 5 days, rates of protein synthesis in untreated septic rats remained depressed. Treatment of septic animals with amrinone for 5 days prevented the sepsis-induced inhibition of protein synthesis by abolishing the inhibition of peptide-chain initiation and restoring translational efficiency to control values. In contrast, amrinone treatment of control rats for 5 days did not cause an accretion of muscle protein or augment protein synthesis. Ten days after induction of sepsis, there were no differences in rates of protein synthesis, RNA content, or translational efficiency in septic animals compared with control or amrinone-treated septic rats. Thus, amrinone prevented the sepsis-induced abnormalities in skeletal muscle protein synthesis.

The architecture of the atrioventricular conduction axis in dog compared to man: its significance to ablation of the atrioventricular nodal approaches

AV Node in Dog and Man.

INTRODUCTION

Advances in treating patients with dual atrioventricular nodal pathways have called for a better understanding of the morphology of the approaches to the atrioventricular node. In this respect, it has recently been suggested that, in dog, anatomically discrete muscle bundles originating from the sinus node represent the substrate of the dual pathways recognized electrophysiologically in patients with atrioventricular nodal reentrant tachycardia. This concept is at odds with most anatomic studies of the human specialized atrioventricular junctional area. In this study, therefore, we studied histologically the junctional area in dog hearts, comparing them with our own findings in human heart and the descriptions of the earliest investigators.

METHODS AND RESULTS

Five dog and six human hearts were prepared for histology and sectioned serially in different planes. Reconstructions were then made from each of three dog and two human hearts sectioned in orthogonal planes. Gross differences in the anatomy of the atrioventricular junctional area and in the structure of the conduction system were obvious between dog and human hearts. The penetrating portion of the conduction axis was longer in the dog, being much more extensively embedded in the central fibrous body. The atrioventricular node, in both dog and man, was composed of a zone of transitional cells overlying a compact region. The zone of transitional cells in the dog was more extensive posteriorly than anteriorly. No bundles insulated anatomically by fibrous tissue were found either in the internodal atrial myocardium or in the approaches to the atrioventricular node. Our findings in both dog and man are comparable with the initial descriptions of the atrioventricular junctional area.

CONCLUSION

Although the disposition of the conduction system in dog and man is basically similar, there are important differences which relate to the gross anatomy. The anatomic substrate for functional duality of the inputs to the atrioventricular node remains unclear, since our study confirms that the concept of insulated atrionodal tract has no morphologic basis.

Plasma cytokine determinations in emergency department patients as a predictor of bacteremia and infectious disease severity

OBJECTIVE

To determine the predictive value of plasma interleukin (IL)-6 and tumor necrosis factor-alpha (TNF) measurements in assessing bacteremia and subsequent morbidity and mortality rates in emergency department patients.

DESIGN

Prospective case series.

SETTING

Emergency department and inpatient services of a large urban university hospital.

PATIENTS

A total of 100 patients admitted through the emergency department with signs of infection and the presumptive diagnosis of bacteremia.

INTERVENTIONS

Blood samples were collected for cytokine determinations.

MEASUREMENTS AND MAIN RESULTS

IL-6 and TNF concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in plasma samples obtained on patient admission to the emergency department. Patient's hospital course and culture results were documented by chart review. Severity of patient illness was estimated serially using the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system at entry into the study, and then again at 24 and 48 hrs. A quantified, subjective assessment of the severity of patient illness was recorded by the admitting physician in the emergency department. Multivariate logistic regression analysis using the variables of plasma IL-6 concentrations, TNF concentrations, APACHE II score at entry, physician assessment of illness severity, and patient age indicated that of these variables, only plasma IL-6 concentrations predicted bacteremia (p = .006) and death from infection (p = .009). A plasma IL-6 concentration > or = 2.0 ng/mL detected bacteremia with a positive predictive value of 72.7%, a sensitivity of 42.1%, and a specificity of 96.7%. Plasma TNF concentrations predicted mortality from all causes (p = .009) as did physician assessment of illness severity (p = .001). Increased APACHE II scores predicted the use of vasopressor medications (p = .002), length of hospital stay (p = .001), and subsequent increased APACHE II scores (p = .001) but did not predict bacteremia, death from infection, or death from all causes. Greater patient age predicted admission to the intensive care unit (p = .016).

CONCLUSIONS

Measurement of plasma IL-6 concentrations in a population of emergency department patients with apparent bacterial infections predicted bacteremia and death from infection. The characteristics of the test indicated a potential use in selecting patients for the administration of novel therapies for sepsis.

Characterization of the iron-sulfur clusters in ferredoxin from acetate-grown Methanosarcina thermophila

Ferredoxin from Methanosarcina thermophila is an electron acceptor for the CO dehydrogenase complex which decarbonylates acetyl-coenzyme A and oxidizes the carbonyl group to carbon dioxide in the pathway for conversion of the methyl group of acetate to methane (K. C. Terlesky and J. G. Ferry, J. Biol. Chem. 263:4080-4082, 1988). Resonance Raman spectroscopy and electron paramagnetic resonance spectroelectrochemistry indicated that the ferredoxin contained two [4Fe-4S] clusters per monomer of 6,790 Da, each with a midpoint potential of -407 mV. A [3Fe-4S] species, with a midpoint potential of +103 mV, was also detected in the protein at high redox potentials. Quantitation of the [3Fe-4S] and [4Fe-4S] centers revealed 0.4 and 2.1 spins per monomer, respectively. The iron-sulfur clusters were unstable in the presence of air, and the rate of cluster loss increased with increasing temperature. A ferredoxin preparation, with a low spin quantitation of [4Fe-4S] centers, was treated with Fe2+ and S2-, which resulted in an increase in [4Fe-4S] and a decrease in [3Fe-4S] clusters. The results of these studies suggest the [3Fe-4S] species may be an artifact formed from degradation of [4Fe-4S] clusters.

Cytokines inhibit fatty acid oxidation in isolated rat hepatocytes: synergy among TNF, IL-6, and IL-1

We have developed an in vitro rat hepatocyte model in which cytokines inhibit fatty acid oxidation. Cytokine administration resulted in decreased fatty acid oxidation, ketone body production and acetyl CoA/CoA ratios. The inhibitory effects of TNF on fatty acid oxidation were enhanced by either IL-1 or IL-6. TNF (20 U/ml) + IL-6 (30 ng/ml) produced maximal inhibition, whereas IL-1 enhanced inhibition at submaximal TNF concentrations. The key to our model is that substrate input into the tricarboxylic acid cycle in the form of either alanine or pyruvate was required for cytokine mediated inhibition of fatty acid oxidation. Alanine or pyruvate may serve as a source for increased production of malonyl CoA, a potent inhibitor of fatty acid oxidation. We hypothesize that cytokines cause an inappropriate switch from fatty acid oxidation to fatty acid synthesis which has serious consequences for energy levels in the liver and can lead to end organ failure.

Cytokine elevations in critically ill infants with sepsis and necrotizing enterocolitis

We hypothesized that plasma levels of cytokines such as interleukin-6 and tumor necrosis factor (TNF) are elevated in critically ill infants with sepsis and necrotizing enterocolitis (NEC) and that the magnitude of their elevation is correlated with mortality rate. We measured plasma levels of interleukin-6 and TNF in 62 newborn infants with suspected sepsis or NEC. Eighteen infants had bacterial sepsis, 9 had bacterial sepsis plus NEC, and 15 had NEC but negative culture results. Twenty comparably ill infants with negative results on culture of systemic specimens served as study control subjects. Interleukin-6 levels were five- to tenfold higher in infants with bacterial sepsis plus NEC at the onset of disease than in infants with bacterial sepsis alone, in infants with NEC but negative culture results, and in control infants (p < 0.01). These differences persisted throughout the 48-hour study period. Interleukin-6 levels were also significantly higher in nonsurvivors than in survivors (p < 0.001). In contrast, plasma TNF values were not consistently increased in any of the groups. We conclude that plasma interleukin-6 is a more reliable indicator of bacterial sepsis and NEC than plasma TNF and may identify infants who might benefit from immunotherapeutic strategies.

In vitro and in vivo effects of granulocyte colony-stimulating factor on neutrophils in glycogen storage disease type 1B: granulocyte colony-stimulating factor therapy corrects the neutropenia and the defects in respiratory burst activity and Ca2+ mobilization

Children with glycogen storage disease (GSD) type 1b are susceptible to recurrent bacterial infections and have chronic neutropenia accompanied by phagocytic cell dysfunction including decreased superoxide anion (O2-) generation, calcium (Ca2+) mobilization, and chemotactic activity. Granulocyte colony-stimulating factor (G-CSF), a cytokine that corrects neutropenia in other diseases, in vitro enhances f-Met-Leu-Phe-triggered neutrophil O2- generation. Short-term pretreatment (15 min) of GSD 1b neutrophils with G-CSF increased the rate of O2- production (p < 0.01); however, this rate was still significantly below the rate of O2- production in control neutrophils. Recombinant human G-CSF (5 micrograms/kg/d) was administered s.c. to a GSD 1b patient. Before treatment, absolute neutrophil counts were < 500/mm3. Two d after G-CSF administration, the absolute neutrophil counts increased to 1333 and remained in the normal range during a 12-mo follow-up period. In vivo, G-CSF therapy increased f-Met-Leu-Phe-stimulated O2- production to 52% of control after 1 mo, and by mo 4, O2- production reached control levels. Our previous studies (J Clin Invest 56:196-202, 1990) demonstrated that decreased O2- production in neutrophils was associated with impaired Ca2+ mobilization. In vivo administration of G-CSF increased f-Met-Leu-Phe-triggered Ca2+ mobilization by neutrophils to 43% of control by mo 1 of G-CSF therapy and to 93% of control by mo 4, thus paralleling the improvements in O2- generation. In contrast, G-CSF therapy had no effect on the defective neutrophil chemotaxis. In summary, G-CSF therapy produced a rapid increase in circulating neutrophils and a gradual correction of O2- production.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon-gamma corrects the respiratory burst defect in vitro in monocyte-derived macrophages from glycogen storage disease type 1b patients

Glycogen storage disease (GSD) type 1b is accompanied by decreased respiratory burst activity in peripheral blood phagocytic cells (i.e. monocytes and neutrophils). To elucidate whether this depressed respiratory burst was due to an intrinsic defect of phagocytic cells or due in part to in vivo host factors, we examined superoxide anion (O2-) production in monocytes from five GSD 1b patients cultured 9 d in vitro to allow for differentiation into macrophages (MDM). O2- production in MDM was measured in response to concanavalin A, fMet-Leu-Phe, and phorbol myristate acetate (PMA) stimulation. GSD 1b MDM had significantly depressed O2- generation with fMet-Leu-Phe and concanavalin A stimulation; however, unlike peripheral blood monocytes, GSD 1b MDM responded to PMA stimulation with O2- production comparable to healthy control donors. The cytokine interferon-gamma (IFN-gamma) has been shown to enhance O2- production in MDM. When GSD 1b MDM were cultured in the presence of IFN-gamma (1 x 10(5) U/L), O2- production in response to fMet-Leu-Phe, concanavalin A, and PMA was enhanced to rates similar to those of control MDM cultured in the presence of IFN-gamma. Thus, the respiratory burst defect observed in circulating phagocytic cells is also present in vitro in cultured GSD 1b MDM. However, in contrast to circulating phagocytic cells, depressed O2- production in GSD 1b MDM is selective to receptor-mediated activation, but not to PMA stimulation. This defect is correctable after short-term treatment with IFN-gamma, suggesting a role for IFN-gamma in treating the phagocytic defect in this disease.

Recombinant human GM-CSF treatment of neutropenia in glycogen storage disease-1b

PURPOSE

Recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF) was administered to two patients with glycogen storage disease, type 1b (GSD-1b), with chronic neutropenia, neutrophil dysfunction, and recurrent infections in an effort to increase neutrophil counts and increase resistance to infections.

PATIENTS AND METHODS

The patients' baseline absolute neutrophil counts (ANC) ranged from 56 to 480 cells/mm3 despite increased granulocyte precursors in the bone marrow. GM-CSF was given s.c. at starting doses of 500 micrograms/m2/day divided into two doses.

RESULTS

After 48 h, ANC rose to 2,025 cells/mm3 and 3,132 cells/mm3, respectively. Absolute eosinophil counts also rose to 1,048 cells/mm3 (24%) and 4,820 cells/mm3 (33%) on days 10 and 9 in the two patients. Although an initial 10-day course of GM-CSF was tolerated in one patient without significant reactions, subsequent s.c. injections of GM-CSF were complicated by increasingly painful local reactions that necessitated discontinuation after 7 to 8 days. Intravenous infusion was associated with a febrile systemic reaction. Despite lack of improvement in neutrophil superoxide anion generation measured in one, both patients demonstrated unusually rapid healing of cutaneous infections on GM-CSF.

CONCLUSION

Our experience suggests that GM-CSF may be useful for short-term treatment of serious infections in GSD-1b. However, alternate dosage schedules or different preparations of GM-CSF to diminish local reactions would be required for long-term maintenance therapy. Granulocyte colony stimulating factor (G-CSF) has also been shown to increase neutrophils in this disease and has not been associated with allergic reactions.

Impairment of calcium mobilization in phagocytic cells in glycogen storage disease type 1b

Patients with glycogen storage disease (GSD) type 1b, in contrast to patients with GSD 1a, are susceptible to recurrent bacterial infections suggesting defective phagocytic function. We have demonstrated a selective defect in respiratory burst activity but not in degranulation by phagocytic cells in GSD 1b but not in GSD 1a. The respiratory burst abnormality in phagocytic cells from GSD 1b patients was associated with impaired calcium mobilization, whereas these processes were normal in GSD 1a patients. Therefore, the alteration in calcium mobilization was an indication of a signalling defect in phagocytic cells from GSD 1b. However, calcium mobilization was normal in lymphocytes, indicating that defective calcium mobilization was not a global finding in circulating leukocytes, but was specific to phagocytic cells. Calcium mobilization in response to ionomycin was reduced suggesting decreased calcium stores in GSD 1b neutrophils. Therefore, altered phagocytic cell function in GSD 1b patients appears to be associated with diminished calcium mobilization and defective calcium stores. This defective calcium signalling was associated with a selective defect in respiratory burst activity but not degranulation.

Alpha-1-antichymotrypsin inhibits the NADPH oxidase-enzyme complex in phorbol ester-stimulated neutrophil membranes

The generation of superoxide anion and release of granule contents are essential to the bactericidal function of neutrophils, but may also contribute to host tissue damage during inflammation. In previous studies (J. Immunol. 146:2388), we have demonstrated that the acute phase reactant alpha-1-antichymotrypsin (ACT), a potent inhibitor of the serine protease cathepsin G, also suppresses superoxide anion generation. The inhibitory effect of ACT was not directly linked to its antiproteolytic activity and may reflect interaction at a site other than its reactive loop. To further characterize the mechanism of inhibition, we investigated the direct effects of ACT on the NADPH oxidase enzyme complex and the signaling pathways that regulate motivation of the respiratory burst. We present evidence that ACT does not intefer with agonist-stimulated calcium mobilization or translocation and activity of protein kinase C. ACT was an effective inhibitor of superoxide anion generation in membrane preparations isolated from PMA-activated cells. These results support the notion that ACT is acting on a component of the active assembled NADPH oxidase complex. Thus, ACT may have an important role in regulation of specific aspects of the inflammatory processes and the modulation of toxic oxygen-based host tissue damage.