P330 A CASE OF SEVERE AORTIC STENOSIS IN A YOUNG PATIENT WITH BICUSPID AORTIC VALVE, FAMILIAL HYPERCHOLESTEROLEMIA AND CALCIFICATION AT THE SINOTUBULAR JUNCTION

Background

Familial hypercholesterolemia (FH) is a disorder characterized by elevated LDL–C and premature vascular calcifications. Aortic stenosis (AS) is the most frequent complication of bicuspid aortic valve (BAV), often requiring aortic valve replacement. Cardiac surgery in patients with severely calcified ascending aorta is challenging.

Case Presentation

A 28 year old male from Albania presented to the ED for dyspnea and low–threshold angina. The patient had family history for CAD and a sister with known FH treated with PCSK9–i. He had BAV, known hypercholesterolemia (max cholesterol 660 mg/dL), treated since 2015 with rosuvastatin plus ezetimibe, with reported irregular intake. He was treated with PCI and bioresorbable vascular scaffold on LAD coronary artery. He underwent surgical removal of limb xanthomas. At admission, the patient was asymptomatic at rest. Cardiac auscultatory findings included an ejection murmur in the aortic area. He presented upper and inferior eyelid xanthelasmas, bilateral calcaneal tendon thickening, elbows and knee xanthoma removal scars. Blood tests were unremarkable, except for lipid profile (LDL–C 443 mg/dL, HDL 36 mg/dL, TG 73 mg/dL). The echocardiography showed BAV, severe AS (Vmax 4,2 m/s, MPG 41 mmHg, AVA 0.46 cm2/m2), EF 60%. A coronary angiography excluded significant stenosis in the epicardial coronary vessels. An aortic CT scan showed sinotubular junction with preserved diameters and severe multiple parietal calcifications, ascending aorta with diffuse atheromatous disease. The patient underwent mechanical aortic valve replacement, ascending aorta thromboendarterectomy, non–coronary sinus enlargement patch, double CABG (SVG–OM, SVG–LAD) due to diffuse hypokinesia of the left ventricle after the interruption of extracorporeal circulation. At a 3–month outpatient re–evaluation, due to the unsatisfactory response to the regular intake of rosuvastatin plus ezetimibe (TC 309 mg/dL, TG 52 mg/dL, HDL 34 mg/dL, LDL–C 264 mg/dL), a PCSK9–i was prescribed. Genetic studies for FH are ongoing.

Discussion

This case underlines the importance of aortic evaluation before aortic valve replacement, even in young FH patients, in which severe aortic calcification can influence surgical approach.

Conclusion

We described the multidisciplinary management of a severe symptomatic AS in a young male with FH and sinotubular junction parietal calcifications, which represented a challenging substrate for valve replacement.

Prevalence and features of delirium in older patients admitted to rehabilitation facilities: a multicenter study

BACKGROUND

Delirium is thought to be common across various settings of care; however, still little research has been conducted in rehabilitation.

AIM

We investigated the prevalence of delirium, its features and motor subtypes in older patients admitted to rehabilitation facilities during the three editions of the "Delirium Day project".

METHODS

We conducted a cross-sectional study in which 1237 older patients (age ≥ 65 years old) admitted to 50 Italian rehabilitation wards during the three editions of the "Delirium Day project" (2015 to 2017) were included. Delirium was evaluated through the 4AT and its motor subtype with the Delirium Motor Subtype Scale.

RESULTS

Delirium was detected in 226 patients (18%), and the most recurrent motor subtype was mixed (37%), followed by hypoactive (26%), hyperactive (21%) and non-motor one (16%). In a multivariate Poisson regression model with robust variance, factors associated with delirium were: disability in basic (PR 1.48, 95%CI: 1.17-1.9, p value 0.001) and instrumental activities of daily living (PR 1.58, 95%CI: 1.08-2.32, p value 0.018), dementia (PR 2.10, 95%CI: 1.62-2.73, p value < 0.0001), typical antipsychotics (PR 1.47, 95%CI: 1.10-1.95, p value 0.008), antidepressants other than selective serotonin reuptake inhibitors (PR 1.3, 95%CI: 1.02-1.66, p value 0.035), and physical restraints (PR 2.37, 95%CI: 1.68-3.36, p value < 0.0001).

CONCLUSION

This multicenter study reports that 2 out 10 patients admitted to rehabilitations had delirium on the index day. Mixed delirium was the most prevalent subtype. Delirium was associated with unmodifiable (dementia, disability) and modifiable (physical restraints, medications) factors. Identification of these factors should prompt specific interventions aimed to prevent or mitigate delirium.

The association between low skeletal muscle mass and delirium: results from the nationwide multi-centre Italian Delirium Day 2017

Introduction

Delirium and sarcopenia are common, although underdiagnosed, geriatric syndromes. Several pathological mechanisms can link delirium and low skeletal muscle mass, but few studies have investigated their association. We aimed to investigate (1) the association between delirium and low skeletal muscle mass and (2) the possible role of calf circumference mass in finding cases with delirium.

Methods

The analyses were conducted employing the cross-sectional “Delirium Day” initiative, on patient 65 years and older admitted to acute hospital medical wards, emergency departments, rehabilitation wards, nursing homes and hospices in Italy in 2017. Delirium was diagnosed as a 4 + score at the 4-AT scale. Low skeletal muscle mass was operationally defined as calf circumference ≤ 34 cm in males and ≤ 33 cm in females. Logistic regression models were used to investigate the association between low skeletal muscle mass and delirium. The discriminative ability of calf circumference was evaluated using non-parametric ROC analyses.

Results

A sample of 1675 patients was analyzed. In total, 73.6% of participants had low skeletal muscle mass and 24.1% exhibited delirium. Low skeletal muscle mass and delirium showed an independent association (OR: 1.50; 95% CI 1.09–2.08). In the subsample of patients without a diagnosis of dementia, the inclusion of calf circumference in a model based on age and sex significantly improved its discriminative accuracy [area under the curve (AUC) 0.69 vs 0.57, p < 0.001].

Discussion and conclusion

Low muscle mass is independently associated with delirium. In patients without a previous diagnosis of dementia, calf circumference may help to better identify those who develop delirium.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40520-021-01950-8.

Cardiac care of Non-COVID-19 patients during the SARS-CoV-2 pandemic: The pivotal role of CCTA

Funding Acknowledgements

Type of funding sources: None.

Aims

To describe the role of coronary CT angiography (CCTA) as the sole available non-invasive diagnostic test for symptomatic patients with suspected CAD in a hub center for cardiovascular emergencies in the presence of limited access to hospital facilities during the COVID-19 pandemic.

Methods and Results

From March 9th to April 30th, during the peak of the COVID-19 pandemic, a consecutive cohort of symptomatic patients with high clinical suspicion of CAD and clinical indication to CCTA were enrolled in a hub hospital in Milan, Italy. When obstructive coronary artery disease was detected (>70% diameter stenosis in a proximal coronary segment or >90% stenosis in any coronary segment) patients were referred to invasive coronary angiography (ICA). Clinical follow-up was assessed in patients in whom ICA was considered deferrable.

Overall, 58 consecutive patients were included. Ten (17.2%) symptomatic patients underwent ICA according to CCTA findings, while in 48 (82.8%) patients ICA was deferred. No clinical events were recorded after a mean follow-up of 49.7 ± 16.8 days. In nine out of ten patients referred to ICA, severe coronary artery disease was confirmed and treated accordingly. Changes in medical therapy were significantly more prevalent in patients with vs. those without CAD at CCTA.

Conclusion

We report a potential pivotal role for CCTA in the triage of non-COVID-19 patients with suspected  CAD during the SARS-CoV-2 pandemic. CCTA may be helpful for identifying patients who necessitate ICA, ensuring adequate resource utilization during the pandemic.

Resources and outcome impact of routine availability of computed tomography perfusion

Funding Acknowledgements

Type of funding sources: None.

Background

Stress computed tomography perfusion (Stress-CTP) is a functional technique that can be added to coronary computed tomography angiography (cCTA) to improve the management of patients with suspected coronary artery disease (CAD).

Purpose

To determine the impact of routine availability of Stress-CTP added to cCTA in terms of downstream testing, radiation exposure and outcome in patients with high risk or known CAD.

Methods

Patients symptomatic for chest pain, known for CAD, with previous revascularization or with increased pre-test likelihood of CAD, referred for clinically indicated cCTA with Stress-CTP were prospectively enrolled. Data regarding evaluability, overall radiation exposure, invasive and non-invasive downstream testing, hospitalizations, revascularizations, major adverse cardiac events (MACE) as unstable angina, non-fatal myocardial infarction and cardiovascular death after index test were collected at follow-up.

Results

263 consecutive patients were prospectively enrolled (mean age: 65 ± 9 years; male: 79%), of which 162 (62%) had previous revascularization. The mean follow-up was 323 ± 175 days. cCTA and Stress-CTP were fully evaluable in 95% and 99%, respectively. Obstructive CAD and inducible ischaemia were found in 170 (65%) and 129 (49%) subjects, respectively. No significant difference was found between patients with presence or absence of perfusion defects in terms of downstream non-invasive testing (p: 0.229), while patients with inducible ischaemia had more downstream invasive testing, increased overall radiation exposure, more hospitalizations for cardiovascular reasons and revascularization (all endpoints with p: &lt; 0.001). No differences were detected between patients with inducible ischaemia treated with revascularization after index test and patients without inducible ischaemia, even if with obstructive CAD, treated medically in terms of MACE.

Conclusions

Routine implementation of cCTA with Stress-CTP is associated with subsequent low rate of other non-invasive testing, low overall radiation exposure in case of negative Stress-CTP and good prognosis if clinical management is based on combined anatomical and functional information.

Integrated quantitative PIXE analysis and EDX spectroscopy using a laser-driven particle source

Among the existing elemental characterization techniques, particle-induced x-ray emission (PIXE) and energy-dispersive x-ray (EDX) spectroscopy are two of the most widely used in different scientific and technological fields. Here, we present the first quantitative laser-driven PIXE and laser-driven EDX experimental investigation performed at the Centro de Láseres Pulsados in Salamanca. Thanks to their potential for compactness and portability, laser-driven particle sources are very appealing for materials science applications, especially for materials analysis techniques. We demonstrate the possibility to exploit the x-ray signal produced by the co-irradiation with both electrons and protons to identify the elements in the sample. We show that, using the proton beam only, we can successfully obtain quantitative information about the sample structure through laser-driven PIXE analysis. These results pave the way toward the development of a compact and multifunctional apparatus for the elemental analysis of materials based on a laser-driven particle source.

1173 Additional role of FFRct and stress CT perfusion in the management of patients with stable chest pain compared to cCTA alone

Background

Computed tomography-derived fractional flow reserve (FFRCT) and stress computed tomography perfusion (stress-CTP) are new techniques that combine anatomy and functional evaluation to improve assessment of coronary artery disease (CAD) using coronary computed tomography angiography (cCTA).

Purpose

This study sought to determine the effect of adding FFRCT and stress-CTP to cCTA alone for assessment of lesion severity and patient management of patients

referred for chest pain.

Methods

289 patients with stable chest pain scheduled for clinically indicated invasive coronary angiography (ICA) plus invasive FFR were evaluated with cCTA, FFRCT, and stress-CTP. Of 289 patients, 147 underwent static stress-CTP, while 142 were evaluated with dynamic stress-CTP.

Management plan with optimal medical therapy (OMT) or percutaneous coronary intervention (PCI) for each patient according to results of each non-invasive technique was recorded, and then compared to what effectively applied according to results of reference standard technique (ICA + FFR). The primary endpoints for the study were the correct allocation of patients to OMT or PCI using cCTA, cCTA + FFRCT and cCTA + stress-CTP, and the correct assessment of non-invasive techniques for all three vessels in relation to angiographically and FFR-defined significance.

Results

Compared to cCTA alone, the addition of FFRCT and stress-CTP to cCTA alone increased the agreement in allocating patients to OMT from 24% to 38% and 44%, respectively, while the addition of FFRCT and stress-CTP to cCTA alone increased the agreement in allocating patients to PCI from 29% to 32% and 36%, respectively. Using ICA + FFR as standard reference, cCTA showed agreement for all three vessels in 56% of patients, while combined approaches of cCTA + FFRCT and cCTA + stress-CTP showed agreement in 66% and 82% of patients, respectively.

Conclusions

The addition of functional assessment with FFRCT or Stress-CTP to cCTA has a substantial effect on the evaluation of the relevance of coronary artery disease and therefore on the management of patients compared to cCTA alone.

P6190Dynamic stress CTP with a whole-heart coverage scanner in addition to cCTA and FFRCT

Background

Recently, new techniques such as dynamic stress computed tomography perfusion (stress-CTP) emerged as potential strategies to combine anatomical and functional evaluation in a one-shot scan. However, previous experience used technology that was associated with high radiation exposure.

Purpose

The aim of the study is to test the diagnostic accuracy of integrated evaluation of dynamic myocardial computed tomography perfusion (CTP) on top of coronary computed tomography angiography (cCTA) plus FFR computed tomography derived (FFRCT) by using a whole-heart coverage CT scanner as compared to invasive coronary angiography (ICA) plus clinically indicate invasive fractional flow reserve (FFR).

Methods

Eighty-five consecutive symptomatic patients scheduled for ICA were prospectively enrolled. All patients underwent rest cCTA followed by stress dynamic CTP with a whole-heart coverage CT scanner. FFRCT was also measured by using the rest cCTA dataset. The diagnostic accuracy to detect functionally significant CAD in a vessel-based model of cCTA alone, cCTA+FFRCT, cCTA+CTP or cCTA+FFRCT+CTP were assessed and compared by using ICA and invasive FFR as reference. The overall effective dose of dynamic CTP was also measured.

Results

The prevalence of obstructive CAD and functionally significant CAD were 77% and 57%, respectively. The sensitivity and specificity of cCTA alone, cCTA+FFRCT and cCTA+CTP, were 83% and 66%, 86% and 75%, 73% and 86%, respectively. Both the addition of FFRCT and CTP improves the area under the curve (AUC: 0.876 and 0.878, respectively) as compared to cCTA alone (0.826, p<0.05). The sequential strategy of cCTA+FFRCT+CTP showed the highest AUC (0.919, p<0.05) as compared to all other strategies. The mean ED for cCTA and stress CTP was 2.8±1.2 and 5.3±0.7 mSv, respectively.

Conclusions

The addition of dynamic stress CTP on top of cCTA and FFRCT provides additional diagnostic accuracy with acceptable radiation exposure.

Impulse control disorder in PD: A lateralized monoaminergic frontostriatal disconnection syndrome?

BACKGROUND

Impulse Control Disorder symptoms (ICD) in Parkinson's disease (PD) has been recently associated by magnetic Resonance imaging with impaired cortico-striatal connectivity, especially between left putamen and frontal associative areas.

METHODS

84 patients entered the study (21 PD-ICD+ and 64 PD-ICD-) and underwent DATSCAN imaging. The striatal tracer uptake was evaluated using BRASS software (Hermes, Sweden). The whole-brain analysis was performed with Statistical Parametric Mapping (SPM).

RESULTS

PD-ICD+ showed a significant reduction of left putaminal and left inferior frontal gyrus tracer uptake compared to PD-ICD-. Functional covariance analysis using left putamen as the seed point showed that, in contrast to ICD-patients, ICD+ patients had no functional covariance with contralateral basal ganglia and ipsilateral cingulate cortex, as index of an impaired inter- and intra-hemispheric dopamine binding in PD-ICD+.

DISCUSSION

the results support and expand the concept of a functional disconnection syndrome linked to ICD symptoms in PD patients through an asymmetric molecular frontostriatal network breakdown with left basal ganglia as central hub.

Ultra-low-dose CT for left atrium and pulmonary veins imaging using new model-based iterative reconstruction algorithm

AIMS

To evaluate the feasibility of ultra-low-dose CT for left atrium and pulmonary veins using new model-based iterative reconstruction (MBIR) algorithm.

METHODS AND RESULTS

Two hundred patients scheduled for catheter ablation were randomized into two groups: Group 1 (100 patients, Multidetector row CT (MDCT) with MBIR, no ECG triggering, tube voltage and tube current of 100 kV and 60 mA, respectively) and Group 2 [100 patients, MDCT with adaptive statistical iterative reconstruction algorithm (ASIR), no ECG triggering, and kV and mA tailored on patient BMI]. Image quality, CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of left atrium (LA) and pulmonary veins, and effective dose (ED) were evaluated for each exam and compared between two groups.No significant differences between groups in terms of population characteristics, cardiovascular risk factors, anatomical features, prevalence of persistent atrial fibrillation and image quality score. Statistically significant differences were found between Group 1 and Group 2 in mean attenuation, SNR, and CNR of LA. Significantly, lower values of noise were found in Group 1 versus Group 2. Group 1 showed a significantly lower mean ED in comparison with Group 2 (0.41 ± 0.04 versus 4.17 ± 2.7 mSv).

CONCLUSION

The CT for LA and pulmonary veins imaging using MBIR is feasible and allows examinations with very low-radiation exposure without loss of image quality.

Comparison between liquid and tablet levothyroxine formulations in patients treated through enteral feeding tube

BACKGROUND

The majority of clinicians suggest that enteral feedings should be held 1-2 h prior to and after L-T4 administration despite lack of data for continuous enteral nutrition.

AIM

The aim of this study was to: (1) compare the thyroid hormonal profile in patients submitted to L-T4 treatment in tablets or liquid formulation with an enteral feeding tube; (2) evaluate the nursing compliance with the two different formulations.

SUBJECTS AND METHODS

20 euthyroid patients submitted to total laryngectomy and thyroidectomy consecutively started L-T4 treatment in tablets (Group T) or in liquid formulation (Group L) with enteral feeding tube the day after surgery. Tablets were crushed before administration and enteral feeding was stopped for 30 min before and after L-T4 treatment, whereas liquid formulation was placed into the nasoenteric tube immediately. A questionnaire about the preparation and administration of thyroxine replacement therapy was given to the nurses.

RESULTS

No difference of TSH, fT4 and fT3 before and after L-T4 treatment was observed among patients of Group L. A slightly serum TSH increase was observed in Group T, but not reaching statistical significance (2.50 ± 1.18 vs 2.94 ± 1.22 mUI/L), whereas no difference in fT4 and fT3 levels was found. Preparation and administration of liquid L-T4 was considered excellent by 12/13 nurses, whereas tablet formulation was considered poor by 10/13.

CONCLUSIONS

Our data showed that liquid L-T4 formulation can be administered directly through feeding tube with no need for an empty stomach, with a significant improvement in therapy preparation and administration by nurses.

The brain in late-onset glycogenosis II: a structural and functional MRI study

BACKGROUND

Late-onset glycogenosis type II (GSD II) is a rare, multisystem disorder mainly affecting limb and respiratory muscles due to acid alpha glucosidase deficiency. Despite evidence at autopsy of glycogen accumulation in the brain, no study exploring brain functions is yet available.

OBJECTIVE

Our objective in this study was to assess brain changes in late-onset GSD II.

METHODS

Each patient underwent a standardized neuropsychological assessment, regional grey-matter (GM) atrophy, and resting-state functional magnetic resonance imaging (RS-fMRI). Functional connectivity maps of the salience (SN) and default-mode (DMN) networks were considered. A group of age- and gender-matched healthy controls was enrolled for MRI comparisons. P values family-wise error (FWE) cluster level corrected inferior to 0.05 were considered.

RESULTS

Nine GSD II patients (age 46.6 ± 8.0; 55% male) were recruited. No significant GM atrophy was found in patients compared with controls (n = 18; age 48.0 ± 9.8,;40% male). Functional connectivity within the SN was selectively reduced in patients, and cingulate gyrus and medial frontal cortex were mainly involved. Accordingly, patients had significant impairment of executive functions (as measured by Wisconsin Card Sorting test), whereas other cognitive domains were within mean normal ranges.

CONCLUSIONS

Our findings extend the clinical spectrum of GSD II by indicating that brain changes occur in this muscular disorder. Above all, these results should lead to better examinations of therapeutic approaches and perspectives for the affected patients. Further studies evaluating in depth these issues are warranted.

Usefulness of chemical-shift MRI in discriminating increased liver echogenicity in glycogenosis

BACKGROUND

Glycogen storage diseases are inherited defects which cause accumulation of glycogen in the tissues. Hepatic steatosis is defined as accumulation of fat within hepatocytes. On sonography, liver shows increased echogenicity both in glycogen storage diseases and steatosis. Liver hyperechogenicity in glycogen storage diseases may depend on accumulation of glycogen and/or fat. Chemical-shift magnetic resonance imaging can discriminate tissues only containing water from those containing both fat and water.

AIM

The primary aim of the present study was to evaluate the usefulness of liver chemical-shift magnetic resonance imaging for detecting liver steatosis in patients with metabolic impairment due to glycogen storage diseases.

SUBJECTS

Twelve patients with type I (n=8) or type III (n=4) glycogen storage diseases were studied and compared to 12 obese-overweight subjects with known liver steatosis. As control group 12 lean normal voluntary subjects were recruited.

METHODS

Liver was evaluated by sonography and chemical-shift magnetic resonance imaging to calculate hepatic fat fraction.

RESULTS

A significant difference in echogenicity between patients with glycogen storage diseases and normal subjects was observed (p<0.05), while this difference was not present between overweight-obese and glycogen storage diseases patients. On the contrary, fat fraction was similar between glycogen storage diseases patients and normal subjects and different between glycogen storage diseases patients and overweight-obese (p<0.05).

CONCLUSION

The present data suggest that chemical-shift magnetic resonance imaging may exclude fat deposition as a cause of liver hyperechogenicity in subjects with glycogen storage diseases.

The voltage-dependent nonselective cation current in human red blood cells studied by means of whole-cell and nystatin-perforated patch-clamp techniques

Human red blood cells (RBC) can be studied by means of whole-cell and nystatin-perforated patch-clamp techniques. In 85% of the whole-cell experiments (n=86) and 69% of the perforated-patch recordings (n=13), steps to positive potentials, from a holding potential of 0 mV, induced a slow-activating non-inactivating persistent outward current which reverted at about 0 mV. The current activation phase fitted well with a two-component exponential curve. Half-maximal conductance was reached at about 42 mV. Na+ and K+ carried this current, which was not affected by 20 nM charybdotoxin or 20 mM TEA, but was reduced following a partial substitution of extracellular Cl- by tartrate. This current has characteristics similar to the single-channel currents already described in RBC and may be involved in the rapid adaptations of these cells in the circulation.

Changes in extracellular Ca2+ can affect the pattern of discharge in rat thalamic neurons

1. The aim of this study was to investigate some of the cellular mechanisms involved in the effects caused by changes in extracellular Ca2+ concentration ([Ca2+](o)). 2. Current- and voltage-clamp experiments were carried out on acutely isolated thalamic neurons of rats. 3. Increasing [Ca2+](o) alone induced a transition of the discharge from single spike to burst mode in isolated current-clamped neurons. 4. Increasing [Ca(2+)](o) caused the voltage-dependent characteristics of the low voltage-activated (LVA) transient Ca2+ currents to shift towards positive values on the voltage axis. Changing [Ca2+](o) from 0.5 to 5 mM caused the inactivation curve to shift by 21 mV. 5. Extracellular Ca2+ blocked a steady cationic current. This current reversed at -35 mV, was scarcely affected by Mg2+ and was completely blocked by the non-selective cation channel inhibitor gadolinium (10 microM). The effect of [Ca2+](o) was mimicked by 500 microM spermine, a polyamine which acts as an agonist for the Ca(2+)-sensing receptor, and was modulated by intracellular GTP-gamma-S. 6. At the resting potential, both the voltage shift and the block of the inward current removed the inactivation of LVA calcium channels and, together with the increase in the Ca2+ driving force, favoured a rise in the low threshold Ca2+ spikes, causing the thalamic firing to change to the oscillatory mode. 7. Our data indicate that [Ca2+](o) is involved in multiple mechanisms of control of the thalamic relay and pacemaker activity. These findings shed light on the correlation between hypercalcaemia, low frequency EEG activity and symptoms such as sleepiness and lethargy described in many clinical papers.

Effects of extracellular Ca2+ on membrane and seal resistance in patch-clamped rat thalamic and sensory ganglion neurons

We studied the effects of [Ca2+]ext changes on seal resistance in patch-clamp experiments. Recordings were made on rat peripheral and thalamic neurons. Increasing [Ca2+]ext from 0.5 to 4.5 mM, reduced the ionic currents evoked at potentials from -100 to +50 mV, in cell-attached recordings, in all the neurons tested. The effect was greater at negative potentials. The change in seal conductance (deltaG) decreased with higher resistance seals and became very low over 1 Gohm (<0.5 nS). However, the ratio deltaG/G(0.5 Ca2+) rose from close to 0 up to 0.6, indicating that Ca2+ has a stronger effect when the microelectrode and the membrane are sealed more tightly. These findings suggest that changes in seal resistance may be misleading in experiments in which extracellular Ca2+ changes are used.

Multiple modulatory effects of dopamine on calcium channel kinetics in adult rat sensory neurons

1. The aim of this research was to study the modulatory effects induced on high-voltage-activated (HVA) calcium channels and pharmacologically isolated subtypes through dopamine receptor activation. 2. The experiments were carried out on acutely isolated adult rat sensory neurons, recorded by means of the whole-cell patch-clamp technique. 3. At saturating concentrations dopamine was effective in inducing: (a) a voltage-dependent prolongation of activation kinetics, (b) a voltage-independent scaling down of the currents without any changes in activation and inactivation kinetics, and (c) an acceleration of inactivation kinetics, not affected by a positive conditioning prepulse. 4. These three inhibitory effects were observed on N- and P/Q-type currents, whereas only a voltage-independent scaling up and/or scaling down was observed on L-type current. 5. The inhibitory effects were sometimes observed in isolation in different neurons, but more frequently they were variously combined in the same cell. A correlation analysis of these effects shows no relationship between them, corroborating the conclusion that they are mechanistically distinct. 6. The existence of an inactivating effect accounts for the occurrence of a voltage-dependent inhibitory effect in some cells without an apparent slowing down of activation kinetics, since the increased inactivation may mask the slow component of the activation. 7. The multiple modulatory effects on calcium channels, even on pharmacologically separated N-, L- and P/Q-currents, suggest that pharmacological and functional classifications do not necessarily match completely. 8. The multiple modulatory effects on HVA calcium currents may play a prominent role both in controlling the integrative properties of neurons and in regulating output at a presynaptic level.

Calcium influx in rat thalamic relay neurons through voltage-dependent calcium channels is inhibited by enkephalin

High and low voltage-activated, transient (HVA and LVA,T) Ca2+ currents are crucial in determining the characteristic thalamic firing pattern, during the oscillatory mode. The modulatory effects induced by D-ala2-D-leu5-enkephalin (DADLE) on voltage-dependent Ca2+ channels have been investigated on acutely dissociated neurons from rat ventro-basal (VB) thalamus, by means of whole cell patch-clamp technique. DADLE (400 nM) reduced HVA Ca2+ channel currents in 37 out of 44 cells tested (-53 +/- 5.3% to 0 mV test potential, n = 24,). In 50% of the cases DADLE induced an effect which was persistent at all the potentials tested, i.e. a voltage-independent one. In the remaining neurons, the inhibition partially or totally disappeared on the currents evoked at the highest potentials. DADLE was also able to inhibit LVA Ca2+ channels (-40% in five out of 12 cells). In conclusion, thalamic relay neurons present opioid receptors negatively coupled to both HVA and LVA Ca2+ channels. The presence of two inhibitory effects of DADLE on the total HVA Ca2+ channels has been observed, and they are distinguishable on the basis of their sensitivity to voltage. It is suggested that Ca2+ current modulation may play a role in the production and tuning of the rhythmic burst discharge in these neurons.

The ASGE guidelines for the appropriate use of upper gastrointestinal endoscopy in an open access system

AIMS

This multicenter and prospective study was aimed at examining the appropriate use of upper gastrointestinal endoscopy in an open access system (primary endoscopy) using the American Society for Gastrointestinal Endoscopy (ASGE) guidelines. We also wished to see whether these guidelines can be easily used in clinical practice.

MATERIALS AND METHODS

Three thousand four hundred fourteen upper gastrointestinal endoscopies performed in seven endoscopy units of different size were studied prospectively. The real indication, to be with the guidelines, was determined by the endoscopist before performing the examination, based on a patient's history.

RESULTS

Seven hundred eighty-one (23%) endoscopies were "generally not indicated," according to ASGE guidelines, and were distributed as follows: follow-up of duodenal ulcer healing (33%), follow-up of other healed benign diseases (24%), surveillance of gastric atrophy, pernicious anemia, metaplasia, treated achalasia, and prior gastric intervention (14%), diagnosis of dyspepsia considered functional in origin (13%), and uncomplicated heartburn responding to medical therapy (7%). Endoscopies "generally not indicated" accounted for 23% in the bigger endoscopy units, 24% in the average sized units, and 22% in the smaller ones. They accounted for 32% when the examination was prescribed by family doctors, 17% when prescribed by internists, 19% by surgeons, and 14% by gastroenterologists (p < 0.001). Eighty-six (2.5%) endoscopies were done for indications not provided in the guidelines.

CONCLUSIONS

This study shows that ASGE guidelines are complete and easy to use and that the rate of inappropriate indications in an open access system can be considerable. They occurred mainly in the follow-up of healed benign disease and were more frequent when the examination was prescribed by the family doctor.

Low-voltage activated calcium channels are differently affected by nimodipine

Voltage-dependent Ca2+ channels in adult rat sensory neurones were studied as far as their characterization and nimodipine effects are concerned, using patch-clamp whole-cell technique. Low-voltage activated (LVA) Ca2+ currents were identified according to activation and inactivation kinetics and sensitivity to amiloride. Nimodipine (10 nM) caused a decrease in LVA Ca2+ current amplitude (-40% +/- 2.2 s.e.m., n = 11 out of 30 with LVA Ca2+ currents). Conversely, in 6 neurones out of 30 nimodipine increased the Ca2+ current amplitude (+ 10% +/- 2). In some unaffected neurones (n = 5) nimodipine was also tested at higher concentrations (up to 5 microM) without any appreciable effect. In conclusion, nimodipine was partly able to block LVA calcium channels even at nanomolar concentrations. Supposing nimodipine acts directly on the channel, it can be assumed that there may be different types of LVA calcium channels in sensory neurones.

Two distinct modulatory effects on calcium channels in adult rat sensory neurons

D-ala2-D-leu5-enkephalin (100 to 1000 nM) reduces HVA Ca2+ currents of approximately 60% in 92% of the adult rat sensory neurons tested. In 80% of the cells sensitive to enkephalin, the reduction in Ca2+ current amplitude was associated with a prolongation of the current activation that was relieved by means of conditioning pulses in a potential range only about 10 mV positive to the current activation range in control conditions. The time course of the current activation was fitted to a single exponential in control, (tau = 2.23 msec +/- 0.14 n = 38) and double exponential with enkephalin, (tau 1 = 2.18 msec +/- 0.25 and tau 2 = 9.6 msec +/- 1, test pulse to -10 mV, 22 degrees C). A strong conditioning depolarizing prepulse speeded up the activation time course, completely eliminating the slow, voltage-sensitive exponential component, but it was only partial effective in restoring the current amplitude to control values. The voltage-independent inhibitory component that was not relieved could be recovered only by washing out enkephalin. In the remaining 20% of the cells affected, enkephalin decreased Ca2+ current amplitude without prolongation of Ca2+ channel activation. In these cases the conditioning voltage pulse was not effective in relieving the inhibition that persisted also at strong positive test potentials, on the outward currents. The voltage-dependent inhibition occurred slowly after enkephalin superfusion (tau congruent to 12 sec), whereas the voltage-independent one developed about ten times more rapidly. Dopamine (100 microM) could also induce both voltage-dependent and independent modulations. In some sensory neurons the two different effects were separately induced by the two substances. GTP-'y-S (100 ,uM) intracellularly perfused mimicked both the modulatory effects. The two modulations may have different functions in processing nociceptive inputs.

Effects of acetyl-L-carnitine on the survival of adult rat sensory neurons in primary cultures

Acetyl-L-carnitine produces a significant increase in the survival time-course of adult rat sensory neurons maintained in primary cultures up to 40 days. The analysis of our data suggests that 200 microM acetyl-L-carnitine added to the medium, slows down neuronal decay especially in the first 10 days in vitro, sparing a fraction of cells which would otherwise be lost. Patch-clamp recordings from these neurons show that superfusion with acetyl-L-carnitine (100-1000 microM) does not induce any membrane current. In addition an agonist muscarinic effect particularly concerning high-voltage activated calcium channel modulation appears to be ruled out. In conclusion our data favour the role of acetyl-L-carnitine in the trophism of sensory neurons in adult rats. In agreement with other in vivo experiments our data reinforce the hypothesis that this substance might be involved in reducing neuronal loss observed in nervous system aging.