Cirrhotic cardiomyopathy: Predictors of major adverse cardiac events and assessment of reversibility after liver transplant

BACKGROUND

Major adverse cardiac events (MACE) are a leading cause of morbidity and mortality after orthotopic liver transplantation (OLT). Cirrhotic cardiomyopathy (CCM), initially described in 2005 and revised in 2019, is a source of MACE in patients after OLT. We sought to identify CCM-related predictors of MACE at one-year follow-up after OLT and assess for reversibility of CCM post-OLT.

METHODS

This is a retrospective study of adult patients who underwent OLT between 2009 and 2019. All patients had transthoracic echocardiography pre-and post-OLT. Patients with a left ventricular ejection fraction <50 % pre-OLT were excluded. MACE was defined as death, myocardial infarction, congestive heart failure hospitalization, or cardiac arrest.

RESULTS

In total, 131 patients were included in this study, of whom 103 and 23 patients met the 2005 and 2019 criteria, respectively. During the follow-up period, 42 patients had MACE and these patients were more likely to have ascites (p = 0.003), hepatorenal syndrome (p = 0.019), and CCM per 2005 criteria (p = 0.023). There were no significant differences between pre-OLT CCM per 2019 criteria (19 % vs 17 %, p = 0.758) or MELD-Na score (21.24 vs 19.40, p = 0.166) for MACE post-OLT. Per the 2005 criteria, 35 of 103 patients recovered and these patients were less likely to have MACE post-OLT (p = 0.012). Per the 2019 criteria, 13 of 23 patients recovered post-OLT but this low number precluded further statistics.

CONCLUSION

The 2005 Montreal criteria for CCM were an independent predictor of MACE at one-year follow-up post-OLT while the 2019 CCC criteria for CCM were not. In addition, the 2005 Montreal criteria were more prevalent when compared to 2019 CCC criteria. Finally, the 2005 Montreal criteria were reversible post-OLT 34 % of the time compared to the 2019 CCC criteria which were reversible 57 % of the time.

Assessment of Vascular and Valvular Calcification Improves Screening for Coronary Artery Disease Before Liver Transplantation

Coronary artery disease (CAD) is common in patients with cirrhosis who underwent orthotopic liver transplantation (OLT) evaluation and stress echocardiogram (echo) has a low sensitivity in these patients. This study aimed to assess the impact of vascular and valvular calcification on the ability to identify CAD before OLT. We performed a case-control study of 88 patients with and 97 without obstructive CAD who underwent OLT evaluation. All patients had a preoperative stress echo, abdominal computed tomography, and cardiac catheterization. A series of nested logistic regression models of CAD were fit by adding independent variables of vascular (including coronary) calcification, aortic and mitral valve calcification, age, gender, and history of diabetes mellitus requiring insulin to a baseline model of abnormal stress echo. Compared with stress echo alone, identification of the presence or absence of vascular and valvular calcification on routine preoperative computed tomography and echo improved the diagnostic performance for the detection of CAD based on coronary angiogram when combined with stress echo in patients with cirrhosis who underwent OLT evaluation (area under the curve 0.58 vs 0.73, p <0.001), which is even further improved when age, gender, and history of diabetes mellitus requiring insulin are considered (area under the curve 0.58 vs 0.80, p <0.001). Achieving target heart rate (p = 0.92) or rate-pressure product >25,000 (p = 0.63) did not improve the ability of stress echo to identify CAD. In conclusion, the use of abdominal vascular, coronary artery, and valvular calcification, along with stress echo, improves the ability to identify and rule out obstructive CAD before OLT compared with stress echo alone.

Hepatic Ischemia/Reperfusion Injury After Liver Transplantation Is Not Associated with Early Impairment of Left Ventricular Ejection Fraction

BACKGROUND Early myocardial dysfunction is a known complication following liver transplant. Although hepatic ischemia/reperfusion injury (hIRI) has been shown to cause myocardial injury in rat and porcine models, the clinical association between hIRI and early myocardial dysfunction in humans has not yet been established. We sought to define this relationship through cardiac evaluation via transthoracic echocardiography (TTE) on postoperative day (POD) 1 in adult liver transplant recipients. MATERIAL AND METHODS TTE was performed on POD1 in all liver transplant patients transplanted between January 2020 and April 2021. Hepatic IRI was stratified by serum AST levels on POD1 (none: <200; mild: 200-2000; moderate: 2000-5000; severe: >5000). All patients had pre-transplant TTE as part of the transplant evaluation. RESULTS A total of 173 patients underwent liver transplant (LT) between 2020 and 2021 and had a TTE on POD 1 (median time to echo: 1 day). hIRI was present in 142 (82%) patients (69% mild, 8.6% moderate, 4% severe). Paired analysis between pre-LT and post-LT left ventricular ejection fraction (LVEF) of the entire study population demonstrated no significant decrease following LT (mean difference: -1.376%, P=0.08). There were no significant differences in post-LT LVEF when patients were stratified by severity of hIRI. Three patients (1.7%) had significant post-transplant impairment of LVEF (<35%). None of these patients had significant hIRI. CONCLUSIONS hIRI after liver transplantation is not associated with immediate reduction in LVEF. The pathophysiology of post-LT cardiomyopathy may be driven by extra-hepatic triggers.

Abstract 178: Improving Cardiac Rehab Attendance By Providing Transportation Services And Removing Cost

For more than a decade, Cardiac Rehabilitation (CR) has been a Class IA indication for cardiovascular patient populations. While the benefits of CR are well published, enrollment and attendance barriers persist. The overall objective of the PACE Project is to increase enrollment and completion of a CR program in an urban academic health center. It addresses two known barriers to patient CR participation: transportation and affordability. Our hypothesis is that Phase II CR enrollment and attendance can be increased by providing free transportation and removing patient out-of-pocket expenses. The study recruitment period was October 2019 to March 2021, with a pause in services and recruitment during the initial COVID-19 pandemic lockdown. Patient were offer PACE participation during their hospitalization. Once consents were obtained, the standard processes to schedule and enroll in Phase II cardiac rehab and exercise prescription were adhered. Patients were responsible for calling and scheduling transportation services for their CR sessions. Upon completion of the study, 73% (41/56) patients attended at least one Phase II session, with an average of 15 session per attendee. This compared to previously published national participation of 8.2% or 32.6%, of at least one session, depending upon in-patient CR referral. The study had a Phase II graduation rate of 32% (13/41). Transportation was utilized in 10.7% (6/56) of participants, with billed mileage ranging from 1-5 miles. Those utilizing transportation services were all female, with 83% (5/6) being women of color. Out-of-pocket co-payments were observed for 41.4% (17/41) of attendees. For those with co-payments, an average of $40, with a range $2-$60, per session was observed. CR is a proven guideline directed intervention to reduce secondary cardiac events. Our study suggest the removal of frequently cited barriers to participation, cost and transportation, is associated with improved CR participation.

MiR-150 Attenuates Maladaptive Cardiac Remodeling Mediated by Long Noncoding RNA MIAT and Directly Represses Profibrotic Hoxa4

BACKGROUND

MicroRNA-150 (miR-150) plays a protective role in heart failure (HF). Long noncoding RNA, myocardial infarction-associated transcript (MIAT) regulates miR-150 function in vitro by direct interaction. Concurrent with miR-150 downregulation, MIAT is upregulated in failing hearts, and gain-of-function single-nucleotide polymorphisms in MIAT are associated with increased risk of myocardial infarction (MI) in humans. Despite the correlative relationship between MIAT and miR-150 in HF, their in vivo functional relationship has never been established, and molecular mechanisms by which these 2 noncoding RNAs regulate cardiac protection remain elusive.

METHODS

We use MIAT KO (knockout), Hoxa4 (homeobox a4) KO, MIAT TG (transgenic), and miR-150 TG mice. We also develop DTG (double TG) mice overexpressing MIAT and miR-150. We then use a mouse model of MI followed by cardiac functional, structural, and mechanistic studies by echocardiography, immunohistochemistry, transcriptome profiling, Western blotting, and quantitative real-time reverse transcription-polymerase chain reaction. Moreover, we perform expression analyses in hearts from patients with HF. Lastly, we investigate cardiac fibroblast activation using primary adult human cardiac fibroblasts and in vitro assays to define the conserved MIAT/miR-150/HOXA4 axis.

RESULTS

Using novel mouse models, we demonstrate that genetic overexpression of MIAT worsens cardiac remodeling, while genetic deletion of MIAT protects hearts against MI. Importantly, miR-150 overexpression attenuates the detrimental post-MI effects caused by MIAT. Genome-wide transcriptomic analysis of MIAT null mouse hearts identifies Hoxa4 as a novel downstream target of the MIAT/miR-150 axis. Hoxa4 is upregulated in cardiac fibroblasts isolated from ischemic myocardium and subjected to hypoxia/reoxygenation. HOXA4 is also upregulated in patients with HF. Moreover, Hoxa4 deficiency in mice protects the heart from MI. Lastly, protective actions of cardiac fibroblast miR-150 are partially attributed to the direct and functional repression of profibrotic Hoxa4.

CONCLUSIONS

Our findings delineate a pivotal functional interaction among MIAT, miR-150, and Hoxa4 as a novel regulatory mechanism pertinent to ischemic HF.

Medication-assisted treatment and self-help group participation among military veterans with opioid or alcohol use disorder

INTRODUCTION

Medication-assisted treatment (MAT) is a combination of behavioural therapy and medications to assist with recovery and has been administered to individuals with alcohol and opioid withdrawal symptoms. Military veterans seeking MAT could have barriers preventing them from receiving the care they desire. The present study sought to compare outcomes in individuals who received MAT or those who participated in self-help groups for opioid or alcohol use disorder. In addition, the present study sought to compare outcomes between veterans and non-military-connected individuals.

METHODS

We used the 2015-2017 United States Treatment Episode Data Set Discharges data from the Substance Abuse and Mental Health Services Administration. The data set included 138 594 unique discharges. A multinomial logistic regression model was used to examine differences in substance use outcomes for veterans/non-veterans in MAT and a self-help group.

RESULTS

Fewer veterans (2.58%) than non-veterans (4.28%) reported usage of MAT. Fewer veterans (38.94%) than non-veterans (40.17%) reported signing up for a self-help group. Finally, those who participated in MAT and a self-help group had a better outcome (66.64%)-defined as no substance use at discharge-than those who only received MAT (43.02%) and those who did not participate in MAT or self-help groups (34.84%).

CONCLUSIONS

Recommendations for future research on MAT and implementation for the veteran population would benefit the literature base.

Cardiogenic shock following cardiac tamponade and Takotsubo in COVID-19

Introduction: Takotsubo is often described as stress-induced cardiomyopathy and is a known cause of heart failure. Objective: Review the clinical course of a young coronavirus disease 2019 (COVID-19) patient who developed Takotsubo following cardiac tamponade. Case presentation: A 42-year-old woman presented to the emergency department with fever, altered mental status and hypoxia. She was ultimately found to be in cardiac tamponade and within 2 hours of a pericardiocentesis she developed Takotsubo and was in cardiogenic shock. Her family decided to place her on comfort measures and she died the same day. Discussion: This case illustrates the increasing number of cardiovascular complications being reported in COVID-19 and highlights the importance of clinicians to be aware of these challenges. Conclusion: Here, we report a distinct presentation of cardiogenic shock in a young COVID-19 patient. The rapid onset of her suspected Takotsubo and the severity of her disease were striking features in this case.

Healthcare utilisation among cancer survivors over 50 years of age

There are now over 104,000 people living in Ireland with a cancer diagnosis. Using The Irish Longitudinal Study on Ageing (TILDA), healthcare utilisation of cancer survivors (aged 50 +) was compared with those without a history of cancer across service providers. Our cancer variable was stratified by time since diagnosis (2-5, 6-10, 11+ years) and type (breast, prostate, colorectal and a miscellaneous group of other cancers). While the probability of cancer survivors accessing GP services was not significant different to respondents without a history of cancer, the probability of an outpatient specialist office visit was 19.5, 11.8 and 14.0 percentage points higher, respectively for those 2-5years, 6-10 years and 11 years or more after their cancer diagnosis and was statistically significant. In Ireland, the pattern of GP and specialist use appears less well defined compared to other European countries. This suggests an overarching policy response is required for cancer survivorship care.

Low molecular weight dextran provides similar optical coherence tomography coronary imaging compared to radiographic contrast media

BACKGROUND

Optical coherence tomography (OCT) coronary imaging requires displacement of red blood cells from the vessel lumen. This is usually accomplished using radiographic contrast. Low molecular weight dextran has low cost and is safe in low volumes. In the present study, we compared dextran with contrast for coronary OCT imaging.

METHODS

Fifty-one vessels in 26 patients were sequentially imaged using manual injection of radiographic contrast (iodixanol) and dextran. OCT images were analyzed at 1 mm intervals to determine the image clarity (defined as a visible lumen border > 270°) and to measure the lumen area and lumen diameter. To correct for the refractive index of dextran, the dextran area measurements were multiplied by 1.117 and the dextran length measurements were multiplied by 1.057.

RESULTS

A total of 3,418 cross-sections (1,709 with contrast and 1,709 with dextran) were analyzed. There were no complications related to OCT imaging or to contrast or dextran administration. Clear image segments were observed in 97.0% vs. 96.7% of the cross-sections obtained with contrast and dextran, respectively (P = 0.45). The mean lumen areas were also similar: 6.69 ± 1.95 mm(2) with iodixanol vs. 7.06 ± 2.06 mm(2) with dextran (correlation coefficient 0.984).

CONCLUSIONS

The image quality and measurements during OCT image acquisition are similar for dextran and contrast. Dextran could be used instead of contrast for OCT imaging, especially in patients in whom contrast load minimization is desired.

Continuous low-level vagus nerve stimulation reduces stellate ganglion nerve activity and paroxysmal atrial tachyarrhythmias in ambulatory canines

BACKGROUND

We hypothesize that left-sided low-level vagus nerve stimulation (LL-VNS) can suppress sympathetic outflow and reduce atrial tachyarrhythmias in ambulatory dogs.

METHODS AND RESULTS

We implanted a neurostimulator in 12 dogs to stimulate the left cervical vagus nerve and a radiotransmitter for continuous recording of left stellate ganglion nerve activity, vagal nerve activities, and ECGs. Group 1 dogs (N=6) underwent 1 week of continuous LL-VNS. Group 2 dogs (N=6) underwent intermittent rapid atrial pacing followed by active or sham LL-VNS on alternate weeks. Integrated stellate ganglion nerve activity was significantly reduced during LL-VNS (7.8 mV/s; 95% confidence interval [CI] 6.94 to 8.66 versus 9.4 mV/s [95% CI, 8.5 to 10.3] at baseline; P=0.033) in group 1. The reduction was most apparent at 8 am, along with a significantly reduced heart rate (P=0.008). Left-sided low-level vagus nerve stimulation did not change vagal nerve activity. The density of tyrosine hydroxylase-positive nerves in the left stellate ganglion 1 week after cessation of LL-VNS were 99 684 μm(2)/mm(2) (95% CI, 28 850 to 170 517) in LL-VNS dogs and 186 561 μm(2)/mm(2) (95% CI, 154 956 to 218 166; P=0.008) in normal dogs. In group 2, the frequencies of paroxysmal atrial fibrillation and tachycardia during active LL-VNS were 1.4/d (95% CI, 0.5 to 5.1) and 8.0/d (95% CI, 5.3 to 12.0), respectively, significantly lower than during sham stimulation (9.2/d [95% CI, 5.3 to 13.1]; P=0.001 and 22.0/d [95% CI, 19.1 to 25.5], P<0.001, respectively).

CONCLUSIONS

Left-sided low-level vagus nerve stimulation suppresses stellate ganglion nerve activities and reduces the incidences of paroxysmal atrial tachyarrhythmias in ambulatory dogs. Significant neural remodeling of the left stellate ganglion is evident 1 week after cessation of continuous LL-VNS.

Intrinsic cardiac nerve activity and paroxysmal atrial tachyarrhythmia in ambulatory dogs

BACKGROUND

Little is known about the relationship between intrinsic cardiac nerve activity (ICNA) and spontaneous arrhythmias in ambulatory animals.

METHODS AND RESULTS

We implanted radiotransmitters to record extrinsic cardiac nerve activity (ECNA; including stellate ganglion nerve activity and vagal nerve activity) and ICNA (including superior left ganglionated plexi nerve activity and ligament of Marshall nerve activity) in 6 ambulatory dogs. Intermittent rapid left atrial pacing was performed to induce paroxysmal atrial fibrillation or atrial tachycardia. The vast majority (94%) of ligament of Marshall nerve activity were preceded by or coactivated with ECNA (stellate ganglion nerve activity or vagal nerve activity), whereas 6% of episodes were activated alone without concomitant stellate ganglion nerve activity or vagal nerve activity. Paroxysmal atrial fibrillation and atrial tachycardia were invariably (100%) preceded (<5 seconds) by ICNA. Most paroxysmal atrial tachycardia events (89%) were preceded by ICNA and sympathovagal coactivation, whereas 11% were preceded by ICNA and stellate ganglion nerve activity-only activation. Most paroxysmal atrial fibrillation events were preceded only by ICNA (72%); the remaining 28% were preceded by ECNA and ICNA together. Complex fractionated atrial electrograms were observed during ICNA discharges that preceded the onset of paroxysmal atrial tachycardia and atrial fibrillation. Immunostaining confirmed the presence of both adrenergic and cholinergic nerve at ICNA sites.

CONCLUSIONS

There is a significant temporal relationship between ECNA and ICNA. However, ICNA can also activate alone. All paroxysmal atrial tachycardia and atrial fibrillation episodes were invariably preceded by ICNA. These findings suggest that ICNA (either alone or in collaboration with ECNA) is an invariable trigger of paroxysmal atrial tachyarrhythmias. ICNA might contaminate local atrial electrograms, resulting in complex fractionated atrial electrogram-like activity.

Finding the ideal place for a psychotherapeutic intervention in a stepped care approach--a brief overview of the literature and preliminary results from the Project PREDICT

AIMS

To provide an overview over empirical evidence regarding stepped care approaches that include psychotherapies. To present own preliminary study results in alcohol dependent patients.

METHODS

Publications were searched in the databases Medline, PsycINFO and the internet search engine Google Scholar. Inclusion criteria were psychosocial treatment and psychiatric disorders. Our own study consists of two steps. In step 1 patients receive anti-craving medication or placebo and Medical Management (MM). After a relapse to heavy drinking patients can step up and after randomization they either continue with the same treatment or they receive additional alcoholism specific psychotherapy (ASP).

RESULTS

Evidence suggests that stepped care might be efficacious in patients with obsessive-compulsive behavior and depression. There is no evidence for efficacy in problem drinkers. Results of our own study show that the completer rate in MM alone is higher than in ASP with MM, but there are no significant differences concerning age, sex and disease severity between completer and non-completer in both study arms.

CONCLUSIONS

Further research with regard to stepped care in alcohol dependent patients is needed. An introduction of the psychotherapy at earlier stages might be sensible.

Reduced event-related current density in the anterior cingulate cortex in schizophrenia

There is good evidence from neuroanatomic postmortem and functional imaging studies that dysfunction of the anterior cingulate cortex plays a prominent role in the pathophysiology of schizophrenia. So far, no electrophysiological localization study has been performed to investigate this deficit. We investigated 18 drug-free schizophrenic patients and 25 normal subjects with an auditory choice reaction task and measured event-related activity with 19 electrodes. Estimation of the current source density distribution in Talairach space was performed with low-resolution electromagnetic tomography (LORETA). In normals, we could differentiate between an early event-related potential peak of the N1 (90-100 ms) and a later N1 peak (120-130 ms). Subsequent current-density LORETA analysis in Talairach space showed increased activity in the auditory cortex area during the first N1 peak and increased activity in the anterior cingulate gyrus during the second N1 peak. No activation difference was observed in the auditory cortex between normals and patients with schizophrenia. However, schizophrenics showed significantly less anterior cingulate gyrus activation and slowed reaction times. Our results confirm previous findings of an electrical source in the anterior cingulate and an anterior cingulate dysfunction in schizophrenics. Our data also suggest that anterior cingulate function in schizophrenics is disturbed at a relatively early time point in the information-processing stream (100-140 ms poststimulus).

Frontal dysfunction in schizophrenia--a new electrophysiological classifier for research and clinical applications

We determined whether schizophrenic patients can be reliably classified with electrophysiological tools. We developed a fully computerized classifier based on 5 minutes of EEG recording during an acoustical choice reaction time task (AMDP-module IV). We included factorized variables from the frequency domain and evoked potentials (N100/P200-complex) from central and frontal electrodes, which were preprocessed in a sample of 150 normal subjects prior to classification. We applied discriminant analyses to the electrophysiological data from depressive, schizophrenic and schizotypal subjects, most of them being unmedicated or drug-naive. The classifier was developed on a training set (33 schizophrenics, 49 normals) and tested on an independent sample (32 schizophrenics, 49 normals). A simple three-variable classifier was found to classify schizophrenics and normals in 77% of those tested correctly. Diagnostic specificity of the classifier proved to be low as the inclusion of depressive patients (n= 60) significantly decreased classification power. It was demonstrated that atypical but not typical neuroleptic drugs may influence the classification results. Correctly classified schizophrenics showed significantly more negative symptoms and slower reaction times than those schizophrenics who were misclassified as normals. In contrast, these misclassified schizophrenics showed a non-significant trend for more positive symptoms and shorter reaction times. As the correctly classified schizophrenics showed increased frontally pronounced delta-activity and decreased signal power of the N100/P200 amplitude, it was concluded that these schizophrenics show dysfunction of the frontal lobe. It is proposed that this new classifier can be useful for clinical and research applications when subtyping of schizophrenics with detection of frontal dysfunction as the aim.

Schizophrenia: reduced signal-to-noise ratio and impaired phase-locking during information processing

OBJECTIVE

This study was performed in order to clarify the mechanisms which underlie the reduced signal-to-noise of event-related potentials in schizophrenic patients. Specifically, we wanted to find out, whether it is reduced activation and/or synchronization (phase-locking) in specific frequency bands of the ongoing EEG which is related to the decreased signal amplitude and signal-to-noise ratio in schizophrenics.

METHODS

We investigated 41 unmedicated schizophrenics (10 of them drug-naïve) and compared them with healthy control subjects (n = 233) as well as unmedicated subjects with schizotypal personality (n = 21), who were considered to be high-risk subjects for schizophrenia, and unmedicated depressive patients (n = 71). We measured event-related activity during an acoustical choice reaction paradigm and calculated the signal-to-noise ratio, signal power and noise for a time interval of 50-200 ms after stimulus presentation. Signal-to-noise ratio was calculated from the power of the averaged trials (signal power) divided by the mean power of the single trials minus the power of the average (noise power). Also, we performed a frequency analysis of the pre- and poststimulus EEG based on a factor analytical approach. Group comparisons were performed with ANCOVA.

RESULTS

As expected, a decreased signal-to-noise ratio of evoked activity was found in the schizophrenic and a non-significant trend in the schizotypal subjects and the depressive patients. We were able to show that the observed decrease is due to a reduced signal power and an increase of absolute noise power. Frequency analysis of the evoked activity revealed that normals, schizophrenics schizotypal subjects and depressive patients increased theta/delta activity between pre- and poststimulus interval to a similar extend. However, this theta/delta-augmentation does not correlate with signal power in schizophrenics. Also, normals and depressive subjects augment coherence between both temporal lobes during information processing, which is not found in schizophrenics and schizotypal subjects. In contrast, these two groups augment frontal lobe coherence, which goes along with an increase of noise.

CONCLUSIONS

Reduced stimulus-induced phase-locking and bitemporal coherence of cortically evoked activity but not a failure to activate the cortex may be responsible for the observed low signal-to-noise ratio during information processing in schizophrenics. Accordingly, schizophrenics increase noise after stimulus presentation instead of building up a signal. This is discussed in the framework of the theory of stochastic resonance.

Neonatal 192 IgG-saporin lesions of basal forebrain cholinergic neurons selectively impair response to spatial novelty in adult rats

The role of the developing cholinergic basal forebrain system on cognitive behaviors was examined in 7 day-old rats by giving lesions with intraventricular injections of 192 IgG-saporin or saline. Rats were subjected to passive avoidance on postnatal days (PND) 22-23, water maze testing on PND 50-60, and a open-field test (in which reactions to spatial and object novelty were measured) on PND 54. Behavioral effects of the lesions were evident only in the open-field test with 5 objects. Unlike controls, the lesioned rats did not detect a spatial change after a displacement of 2 of the 5 objects. Control and lesioned rats, however, showed comparable novelty responses to an unfamiliar object. Lesion effectiveness was confirmed by 75% and 84% decreases in choline acetyltransferase activity in cortex and hippocampus. These results suggest that the developing cholinergic system may be involved in spatial information processing or attention to spatial modifications.

Effect kinetics of desmopressin-induced platelet retention in healthy volunteers treated with aspirin or placebo

Desmopressin is often used for haemostatic treatment in platelet dysfunction, but the effect kinetics of platelet responses and the mechanism of action are poorly known. This study aimed to determine the kinetics of platelet function responses induced by desmopressin in healthy volunteers treated with aspirin or placebo. Another aim was to correlate platelet responses to changes of von Willebrand factor (vWF) in plasma. We measured platelet function with a glass bead retention test, Ivy bleeding time, vWF:Ag and multimeric structure in plasma. Median baseline platelet retention was 12% (normal reference range 16-27%) during aspirin treatment and 18% during placebo. Median peak platelet retention after desmopressin was 33% during aspirin treatment and 34% during placebo. After about 3 h platelet function had returned to baseline. A second desmopressin dose after 3 h stimulated platelet retention to a similar extent as the first dose. There was no correlation between platelet responses and quantitative or qualitative changes of vWF in plasma. Platelet count did not change significantly. Thus, desmopressin's effect on platelet function lasts for about 3 h, but may be prolonged by a second dose immediately thereafter. These findings may have important clinical implications for patients with aspirin-induced platelet dysfunction undergoing surgery.

Neonatal 192 IgG-saporin lesions of basal forebrain cholinergic neurons selectively impair response to spatial novelty in adult rats

The role of the developing cholinergic basal forebrain system on cognitive behaviors was examined in 7 day-old rats by giving lesions with intraventricular injections of 192 IgG-saporin or saline. Rats were subjected to passive avoidance on postnatal days (PND) 22-23, water maze testing on PND 50-60, and a open-field test (in which reactions to spatial and object novelty were measured) on PND 54. Behavioral effects of the lesions were evident only in the open-field test with 5 objects. Unlike controls, the lesioned rats did not detect a spatial change after a displacement of 2 of the 5 objects. Control and lesioned rats, however, showed comparable novelty responses to an unfamiliar object. Lesion effectiveness was confirmed by 75% and 84% decreases in choline acetyltransferase activity in cortex and hippocampus. These results suggest that the developing cholinergic system may be involved in spatial information processing or attention to spatial modifications.

Cortical activation, signal-to-noise ratio and stochastic resonance during information processing in man

OBJECTIVES

The goal of this study was to determine the relation between EEG, event-related potentials and information processing as measured by an acoustical choice reaction time task. In particular, we wanted to find out to what extent reaction-time performance is related to the pre-stimulus EEG activity (frequency domain) and the magnitude of signal power as well as noise power (stimulus-uncorrelated activity) after the tones (time domain).

MATERIALS AND METHODS

For parametrization, EEG-activity was factorized across pre-defined frequency bands and 19 electrode positions, applying spectral power and coherence analysis. Signal power was estimated by calculating the mean power of the evoked single sweeps. Noise power was computed by subtracting the latter minus the power of the average evoked potential. We investigated 254 healthy subjects who had to perform an acoustical choice reaction task during running EEG.

RESULTS

In the frequency domain, it was found that high frontally pronounced delta-power in the pre-stimulus EEG correlates with fast reaction-time performance, which was regarded as the expression of a readiness potential in the frequency domain, reflecting increased cortical activation. In the time domain, fast reaction times were found to be correlated with the amplitude of the event-related potential N100 as well as with the signal power and signal-to-noise ratio of the evoked activity. This result pointed to the frequently described relation between evoked signals and information processing. In accordance with the theory of stochastic resonance, we also found a positive correlation between the magnitude of noise power after the stimulus and reaction-time performance. Besides, noise power was found to be positively correlated with pre-stimulus cortical activation (mainly in the delta and alphal frequency band), whereas no relation was found between pre-stimulus EEG and the signal power of the event-related activity, except for a weak relation to the alpha2 power.

CONCLUSION

Our findings support the notion that information processing is not only dependent on signal strength but also on a certain amount of basic noise, reflecting the overall energy state of the brain.

Liposuction in Dercum's disease: impact on haemostatic factors associated with cardiovascular disease and insulin sensitivity

OBJECTIVE

To study the impact of adipose tissue removal by liposuction on factors associated with increased risk of cardiovascular atherosclerotic disease within the coagulation and fibrinolytic system and glucose metabolism.

DESIGN, SETTING AND SUBJECTS

Liposuction was performed in 53 patients with Dercum's disease. The levels of fibrinogen, von Willebrand factor antigen (VWF:Ag) and plasminogen activator inhibitor type 1 activity (PAI-1) were measured preoperatively, and 2 weeks, 4 weeks and 3 months postoperatively. In a subsample of 10 patients, insulin sensitivity was determined before and 2-4 weeks after surgery using the 2-h euglycaemic hyperinsulinaemic clamp technique. The study was performed as a single-centre study.

MAIN OUTCOME MEASURE

Fibrinogen, PAI-1 and VWF:Ag levels, and glucose uptake before and after removal of adipose tissue.

RESULTS

Weight reduction was sustained throughout the follow-up period with a mean decrease from 90.7 to 86.6 kg (P < 0.0001). There was a slight increase in levels of coagulation factors 2 and 4 weeks postoperatively, probably in reaction to the surgical trauma. After 3 months the values had returned to preoperative levels except for PAI-1, which still showed a slight increase (P < 0.05). In the subsample of 10 patients, glucose uptake was improved (P < 0.05) from a short-term perspective after surgery.

CONCLUSION

Surgical removal of adipose tissue, without change in lifestyle, does not seem to improve the levels of coagulation and fibrinolytic factors associated with cardiovascular atherosclerotic disease, whereas glucose takeup may be facilitated and insulin sensitivity increases from a short-term perspective.

Antidiuretic effect of desmopressin given in hemostatic dosages to healthy volunteers

The aim of this study was to characterize the magnitude and duration of the antidiuretic effects elicited by desmopressin given in hemostatic dosage intravenously (i.v.) (0.3 microg/kg) or intranasally (i.n.) (300 microg) both as single or repeated doses (four i.n. doses with 12-hr intervals) to healthy volunteers. Urine osmolality increased to a maximum median value of 1,087 mOsmol/kg after the single i.v. dose, 1,065 after the single i.n. dose, and 1,071 during the repeated i.n. dosing schedule, and did not differ significantly between the three dosage schedules. The increase lasted for 24 hr after single doses, and 12 hr after the last of the repeated i.n. doses. Serum sodium did not decrease more than normal diurnal variation after single doses, but decreased marginally below the normal reference range in three volunteers after repeated doses. Lowest median serum sodium concentrations after single i.v. and i.n. doses were 140 and 141 mmol/l, respectively, and 139 after repeated i.n. doses. Body weight changed only marginally after single doses, but increased 1.3 kg during repeated dosing. In adult healthy volunteers, single desmopressin doses give an antidiuretic effect lasting for about 24 hr. There is no difference in magnitude or duration between i.v. or i.n. doses. The effect is prolonged as long as the doses are repeated. Serum sodium is only marginally affected by single doses, but tends to decrease after four repeated doses with 12-hr intervals. If desmopressin is repeated for a period of up to 48 hr, fluid intake should be restricted to 2 liters per day in adults.

The demand for health insurance coverage by low-income workers: can reduced premiums achieve full coverage?

OBJECTIVE

To assess the degree to which premium reductions will increase the participation in employer-sponsored health plans by low-income workers who are employed in small businesses.

DATA SOURCES/STUDY SETTING

Sample of workers in small business (25 or fewer employees) in seven metropolitan areas. The data were gathered as part of the Small Business Benefits Survey, a telephone survey of small business conducted between October 1992 and February 1993.

STUDY DESIGN

Probit regressions were used to estimate the demand for health insurance coverage by low-income workers. Predictions based on these findings were made to assess the extent to which premium reductions might increase coverage rates.

DATA COLLECTION/EXTRACTION METHODS

Workers included in the sample were selected, at random, from a randomly generated set of firms drawn from Dun and Bradstreet's DMI (Dun's Market Inclusion). The response rate was 81 percent.

FINDINGS

Participation in employer-sponsored plans is high when coverage is offered. However, even when coverage is offered to employees who have no other source of insurance, participation is not universal. Although premium reductions will increase participation in employer-sponsored plans, even large subsidies will not induce all workers to participate in employer-sponsored plans. For workers eligible to participate, subsidies as high as 75 percent of premiums are estimated to increase participation rates from 89.0 percent to 92.6 percent. For workers in firms that do not sponsor plans, similar subsidies are projected to achieve only modest increases in coverage above that which would be observed if the workers had access to plans at unsubsidized, group market rates.

CONCLUSIONS

Policies that rely on voluntary purchase of coverage to reduce the number of uninsured will have only modest success.

Evidence for the direct interaction of the insulin-like growth factor I receptor with IRS-1, Shc, and Grb10

We have used the yeast two-hybrid system to study the interaction between the IGF-I receptor and two putative substrates, IRS-1 and Shc. In addition, we have identified Grb10 as a protein that binds to the insulin-like growth factor I (IGF-I) receptor. This two-hybrid system (the interaction trap) utilizes a hybrid protein containing the LexA DNA-binding domain fused to the intracellular portion of the IGF-I receptor (LexA-IGFIR beta) and hybrids containing an activation domain fused to either IRS-1 (Ad-IRS-1), Shc (Ad-Shc), or a cDNA library. A positive interaction of LexA-IGFIR beta with the activation domain hybrid results in activation of reporter genes, LacZ and LEU2, in the yeast. Western blotting of extracts from transformed yeast demonstrated that the LexA-IGFIR beta fusion protein was expressed and phosphorylated on tyrosine residues. Coexpression of LexA-IGFIR beta with Ad-IRS-1 resulted in strong activation of both reporter genes; activation did not occur with a kinase-negative receptor mutant. IRS-1 residues 160-516 were sufficient for this strong interaction. Coexpression of LexA-IGFIR beta with Ad-Shc also resulted in strong activation of both LacZ and LEU2 reporter genes. This interaction was also dependent upon a tyrosine kinase-active receptor and required tyrosine 950 in the juxtamembrane region of the receptor. An N-terminal fragment of Shc (amino acids 1-232) interacted almost as strongly as full-length Shc whereas the Shc SH2 domain only activated the more sensitive LEU2 reporter. Full-length Shc was phosphorylated on tyrosine when coexpressed with IGFIR beta but not when coexpressed with the kinase-negative receptor mutant. To identify additional proteins that interact with the IGFIRs, a human fetal brain cDNA library was screened using the interaction trap system. This analysis identified partial cDNAs for Grb10. Coexpression of LexA-IGFIR beta with Ad-Grb10 resulted in strong activation of both LacZ and LEU2 reporter genes; this interaction was dependent upon a tyrosine kinase-active receptor but did not require tyrosine 950.

Bivariate global frequency analysis versus chaos theory. A comparison for sleep EEG data

Various quantitative descriptors for EEG data will be compared taking sleep as an example. In this contribution, Hjorth's mobility and complexity measures will be used to classify sleep stages. The results will be compared with those of a dimensionality analysis. Several authors have shown that the correlation exponent can describe the complexity of sleep EEG data and is able--with the exception of REM sleep--to distinguish significantly between sleep stages. The discriminative power of a bivariate global frequency analysis appears to be superior to that of the correlation exponent. Furthermore a very high statistical correlation between the estimator of fractal dimension and Hjorth's mobility was obtained.

["Neuroadaptation" in long-term cannabis abuse. A clinical and electroencephalographic case study]

This report is about electroencephalographic changes in a twenty-eight year old patient with longterm heavy cannabis use. He was admitted to our hospital after he had developed a depressive-apathetic syndrome. Two days after the last cannabis-intake, the patient had recovered from initial psychopathology and his EEG was completely inconspicuous at this day. Some days later however the patient's behavior became increasingly impulsive and unstable, while his EEG showed a marked disturbed regulation of vigilance. In the following weeks his impulsiveness became less and his EEG returned to normal. We suggest that these alterations may reflect a discontinuation of the initial neuroadaption of the central nervous system to the drug.

Differences in semantic information processing in schizophrenics

Well-established findings in schizophrenics suggest that they have difficulties in interpreting contextual information. We used electrophysiological means to investigate this hypothesis. The N 400 paradigm was used in 29 acute schizophrenic patients and 28 controls. The main findings were a changed topographical distribution of amplitude in the schizophrenic group; that is, a reduced amplitude at the frontal sites and a pronunciation at the occipital sites. We did not find latency differences. When remitted patients (n = 17) were reinvestigated, a negative correlation of the amplitude to the total amount of neuroleptics used was found. These results are discussed in relation to structural and functional findings supporting the hypofrontality hypothesis in schizophrenia.

Lithium effect on smooth pursuit eye movements of healthy volunteers

Smooth pursuit eye movement (SPEM) dysfunctions in major affective disorder patients have been reported to be associated with lithium treatment. We report that SPEM of 13 healthy volunteers, either taking lithium (n = 7) or placebo (n = 6), were not significantly impaired by lithium. This could point to a pathophysiologic difference between affective disorder patients and a normal population.

Increased blink rates in schizophrenics. Influences of neuroleptics and psychopathology

During a standardized visuomotor task, eye blinking, a possible parameter of central dopaminergic activity, was studied in 18 previously medicated and eight drug-naive schizophrenic in-patients in the acute state and during remission. Whereas schizophrenics executed the visuomotor task with the same precision as age- and sex-matched normal control subjects did, the mean blink rate was increased in both schizophrenic groups. During neuroleptic treatment, the mean blink rate was reduced only in the group of drug-naive patients, but not in the previously neuroleptic treated schizophrenics. This varying blinking activity is discussed with respect to the development of neuroleptic tolerance and influence of psychopathology.

[Saccadic reaction times and visuospatial disorders of attention in schizophrenic patients with negative symptoms]

Schizophrenics display various oculomotor disturbances. In this study we investigated saccadic reaction times in 47 unmedicated schizophrenics (ICD-9) as well as 28 age and sex matched normal controls. Using a cluster analysis according to the BPRS we determined two subgroups each with high and low negative symptoms; we expected poorer results from patients with negative symptoms on account of existing attentional deficits. The eye movements were recorded with electrooculography. Stimuli were presented at random with amplitudes of 5 degrees at a minimum and 20 degrees maximally; the distances between the angles were kept as short as possible, and we chose a fast stimulus rate (800, 1.000 and 1.200 ms). Only the group of schizophrenics with pronounced negative symptoms showed significantly delayed saccadic reaction times, whereas other schizophrenic patients did not differ from the controls. An unfavorable course of the illness also was associated with delayed reaction times. The saccadic reaction times were delayed in both the right and left visual field to the same degree. The poorer performance of the schizophrenics with pronounced negative symptoms are being discussed in relation to attentional deficits regarding visuospatial functions.

Optimizing deposition parameters of electron beam evaporated TiO(2) films

A study of the major deposition parameters including source material, oxygen partial pressure, substrate temperature, and deposition rate affecting the optical quality of electron beam evaporated TiO(2) films is presented. After careful optimization of these parameters it is possible to reproducibly deposit TiO(2) films from TiO(2) source material mixed with 5% CeO(2) at an oxygen partial pressure of 5 x 10(-5) Torr, a substrate temperature of 320 degrees C, and a deposition rate of 2 A/s.