Relationship between the modified Rankin Scale and the Barthel Index in the process of functional recovery after stroke.

OBJECTIVE: The modified Rankin Scale (mRS) and the Barthel Index (BI) are the most common clinimetrical instruments for measuring disability after stroke. This study investigated the relationship between the BI and the mRS at multiple time points after stroke. The BI, which is a widely used instrument for longitudinal follow-up post-stroke, was used as reference to determine the effect of time on the sensitivity of the mRS in differentiating functional recovery. METHODS: Ninety-two patients with first stroke and hemispheric brain lesion were evaluated using the BI and mRS at 10 days, 3 and 6 months. The Kruskal-Wallis test was applied to examine median differences in BI among the mRS levels at 10 days, 3 and 6 months with Dunn's correction for multigroup comparison. The Mann and Whitney test was used to compare median differences in BI scores between two aggregations of mRS grades (mRS=0-2, mRS=3-5) at the same time periods after stroke. RESULTS: BI score distribution amongst mRS grades overlapped at 10 days, differentiating only between extreme grades (no disability vs severe disability). At 3 months, independent patients with slight disability could be distinguished from dependent patients with marked disability. At 6 months, grade 2 and 3 overlapped no more, differentiating independence (class 0-2) from dependence (class 3-5). The largest transition to an independent functional status occurred from grade 4, at 3 months. CONCLUSION: Maximum sensitivity of mRS in differentiating functional recovery is reached at six months post-stroke.

Inhibitory effect of synthetic cannabinoids on cytokine production in rheumatoid fibroblast-like synoviocytes.

OBJECTIVE: To verify whether synthetic cannabinoids (CP55,940 and WIN55,212-2) are able to exert an anti-inflammatory effect on rheumatoid fibroblast-like synoviocytes (FLS) by down-regulating cytokine production, and determine whether this effect could be mediated by CB1/CB2 cannabinoid receptors. METHODS: Interleukin-6 (IL-6) and interleukin-8 (IL-8) were assayed in the supernatant from cultured FLS by ELISA method before and after 3 hours of incubation with CP55,940 (10 microM) and WIN55,212-2 (10 microM). Co-stimulation of cells with the cannabinoid receptor antagonists was performed to evaluate receptor involvement in cytokine modulation. All the experiments were conducted in basal conditions and after 1 hour pre-incubation with 0.1 ng/ml IL-1beta. FLS expression of CB1 and CB2 receptor was studied by Western Blot analyses. RESULTS: Both CP55,940 and WIN55,212-2 induced a potent and significant reduction in IL-6 and IL-8 secretion from IL-1beta. stimulated FLS. Although FLS express CB1 and CB2 receptor, cannabinoid receptor antagonists did not significantly modify the inhibition of cytokines secretion induced by CP55,940 and WIN55,212-2. CONCLUSIONS: In vitro, CP55,940 and WIN55,212-2 exert a potent anti-inflammatory effect on rheumatoid FLS via a non-CB1/CB2 receptor mediated mechanism.

Cardiac disease and Rett syndrome.

Rett syndrome (RS) is a neurodevelopmental disease,1 affecting approximately 1 in 10 000-15 000 females. Clinical severity of RS may vary with increasing age, following a four stage model.

Effects of acetyl-L-carnitine on cardiac dysautonomia in Rett syndrome: prevention of sudden death?

There is a higher incidence of sudden death in patients with Rett syndrome than individuals in the general population. Previous studies have implicated cardiac dysautonomia and a long QT interval as causative factors. Because carnitine plays a critical role in cellular metabolism and may have beneficial effects on cardiac and nerve function, we investigated the effects of long-term treatment with acetyl-L-carnitine on heart rate variability and electrocardiographic abnormalities in 10 girls with Rett syndrome and compared the results with 12 control patients (girls with Rett syndrome who were not treated). The age range of the subjects was 2-21 years. The study design called for the evaluation of heart rate variability, corrected QT interval, and QTc dispersion. In the 10 Rett girls treated with acetyl-L-carnitine, a significant increase in heart rate variability was observed. To explain these results, we hypothesize that acetyl-L-carnitine has a neurotrophic action on the cardiac autonomic nervous system. This effect may reduce the risk of sudden death in patients with this syndrome.

Cardiac dysautonomia and serotonin plasma levels in Rett syndrome.

BACKGROUND: In Rett syndrome the autonomic nervous system is abnormal at various levels, from the central to the peripheral nervous system. A role for serotoninergic dysfunction has been suggested. OBJECTIVES: The aim of our study was to evaluate the relation between cardiac dysautonomia (expressed by means of heart rate variability) and plasma serotonin levels in girls affected with Rett syndrome. Heart rate variability and plasma serotonin levels were evaluated in 28 Rett girls aged 1-14 years. A Pearson correlation was used to determine whether there was a relationship between plasma serotonin levels and each heart rate variability parameter. RESULTS: In untreated Rett girls the plasma serotonin levels correlated with the sympathovagal balance, as expressed by the low frequency (LF) to high frequency (HF) ratio (p<0.05). CONCLUSIONS: Our results suggest that cardiac dysautonomia could be linked to serotoninergic dysfunction and that treatment with a serotonin analogue could be useful in improving the sympathovagal balance.

Nerve growth factor plasma levels and ventricular repolarization in Rett syndrome.

Rett syndrome is a severe neurological developmental disorder. In this syndrome, the high incidence of sudden death is correlated with an alteration of ventricular repolarization. The purpose of this study was to evaluate plasmatic levels of nerve growth factor (NGF) in Rett patients with prolonged corrected QT (QTc) interval in comparison with those of Rett patients with normal QTc. We observed 23 female Rett patients (9.9+/-4.7 years). NGF plasma levels and QTc interval were measured in all patients. Student t-test was performed for statistical analysis. NGF plasma levels were significantly lower in Rett patients with QTc interval prolongation (QTc > 0.44 sec) in comparison with Rett patients with a normal QTc interval (4.5+/-4.5 vs 11+/-8.3 pg/ml, p = 0.02). The alteration of NGF levels, observed in Rett patients with a long QTc interval, may explain the presence of an altered ventricular repolarization associated with a higher risk of cardiac arrhythmias.

Blunted increase in plasma adenosine levels following dipyridamole stress in dilated cardiomyopathy patients.

BACKGROUND: Heart failure is characterized by chronically increased adenosine levels, which are thought to express a protective anti-heart failure activation of the adenosinergic system. The aim of the study was to assess whether the activation of adenosinergic system in idiopathic dilated cardiomyopathy (IDC) can be mirrored by a blunted increase in plasma adenosine concentration following dipyridamole stress, which accumulates endogenous adenosine. METHODS: Two groups were studied: IDC patients (n = 19, seven women, mean age 60 +/- 12 years) with angiographically confirmed normal coronary arteries and left ventricular ejection fraction <35%; and normal controls (n = 15, six women, mean age 68 +/- 5 years). Plasma adenosine was assessed by high-performance liquid chromatography methods in blood samples from peripheral vein at baseline and 12 min after dipyridamole infusion (0.84 mg kg-1 in 10 min). RESULTS: At baseline, IDC patients showed higher plasma adenosine levels than controls (276 +/- 27 nM L-1 vs. 208 +/- 48 nM L-1, P < 0.001). Following dipyridamole, IDC patients showed lower plasma adenosine levels than controls (322 +/- 56 nM L-1 vs. 732 +/- 250 nM L-1, P < 0.001). The dipyridamole-induced percentage increase in plasma adenosine over baseline was 17% in IDC and 251% in controls (P < 0.001). By individual patient analysis, 18 IDC patients exceeded (over the upper limit) the 95% confidence limits for normal plasma adenosine levels at baseline, and all 19 exceeded (below the lower limit) the 95% confidence limits for postdipyridamole plasma adenosine levels found in normal subjects. CONCLUSION: Patients with IDC have abnormally high baseline adenosine levels and--even more strikingly--blunted plasma adenosine increase following dipyridamole infusion. This is consistent with a chronic activation of the adenosinergic system present in IDC, which can be measured noninvasively in the clinical theatre.

Acute effects of glibenclamide on reactive hyperaemia in the lower limbs in humans.

Three episodes of 1 min ischemia in the lower limbs in humans reduced the metabolic debt repayment (expressed as AUC of reactive hyperaemia) following more prolonged ischemia (666.6+/-86.6 vs 500.0+/-33.5 ml/100 ml). The administration of the ATP-dependent K(+) channel blocker glibenclamide was associated with a significant reduction in the AUC of reactive hyperaemia (666.6+/-86.6 vs 563.1+/-76.6 ml/100 ml), and with the removal of the protective effect produced by 3 episodes of 1 min ischemia (563.1+/-76.6 vs 551.8+/-71.3 ml/100 ml). Plasma level of glibenclamide reached the peak value of 1.295+/-0.15 micromol/l 2 h after drug administration, ranging around the 1 micromol/l concentration in the following 3 hours. Our findings produce indirect evidence that, similarly to the ischemic preconditioning of the heart, the protective effects towards ischemia of brief repeated episodes of sub-maximal occlusion in the peripheral circulation of the lower limbs in humans are mediated by ATP-dependent K(+) channels.

Progressive cardiac dysautonomia observed in patients affected by classic Rett syndrome and not in the preserved speech variant.

Incidence of sudden death in Rett syndrome is greater than that of the general population, and cardiac electrical instability is a prime suspect cause. The objective of the present study was the evaluation of heart rate variability, a marker of autonomic activity, in females affected by classic Rett syndrome and atypical variants for a possible explanation of the higher risk for sudden death observed in these subjects. Our study showed that girls with classic Rett syndrome had significantly lower heart rate variability and longer corrected QT intervals than in atypical Rett syndrome and age-matched healthy girls. Reduction of heart rate variability progresses with age and with the clinical stage of the syndrome. These results suggest the possible role of the progressive cardiac dysfunction in the sudden death associated with Rett syndrome.

Effects of dipyridamole and adenosine on vasoactive peptides calcitonin gene-related peptide and atrial natriuretic peptide in humans: role of sympathetic activation.

1. It has been observed that dipyridamole (DIP) administration produces equivalent cardiovascular effects at lower systemic adenosine (ADO) plasma concentrations than those obtained with exogenous ADO infusion. This observation led to the identification of DIP for additional 'ischaemia-inducing' mechanisms, possibly based on sympathetic activation. 2. In turn, exogenous ADO administration has proven to elicit a complex neurohumoral response, including an increase in the plasma concentration of catecholamines, associated with augmented levels of the vasoactive peptides calcitonin gene-related peptide (CGRP) and atrial natriuretic peptide (ANP). More particularly, increases in CGRP seem to be dependent on sympathetic activation, while changes in ANP do not. 3. In order to clarify some aspects of the activity of DIP on neurohumoral systems, the effects of administration of DIP and ADO on plasma levels of noradrenaline (NA), CGRP and ANP were studied in healthy volunteers. Haemodynamic parameters were also monitored. 4. Infusion of exogenous ADO produced plasma levels of ADO as high as 1893+/-386 nmol/L, together with a significant increase in plasma levels of CGRP, ANP and NA. Similarly, the infusion of DIP produced augmented plasma concentrations of the examined parameters, with a peak plasma ADO concentration of 470+/-49 nmol/L. 5. At a given ADO plasma concentration of 450+/-10 nmol/L, the increase in CGRP and NA levels with DIP infusion was significantly higher than that observed following the infusion of ADO, whereas the increase in the plasma concentration of ANP following DIP infusion was very similar to that seen following ADO infusion. 6. The physiological background of these findings is based on evidence that DIP displays a greater sympathoexcitatory activity than does exogenous ADO and only the increase in plasma CGRP seems to be mediated, although indirectly, by beta-adrenoceptor stimulation. The exact mechanism of DIP-dependent sympathetic activation remains to be elucidated.

Increase in plasma adenosine during brain ischemia in man: a study during transient ischemic attacks, and stroke.

Adenosine is a "retaliatory metabolite" which accumulates during experimental brain ischemia and has vasodilatory and putative neuroprotective effects. The aim of this study was to assess whether human cerebral ischemia and necrosis-evaluated in the clinical models of transient ischemic attack (TIA) and stroke, respectively-acutely raise plasma adenosine levels. We studied 20 patients: 10 with TIA and 10 with stroke. In all, blood was serially sampled for assessment of plasma adenosine by an high-performance liquid chromatography method. Sampling occurred on peripheral blood during TIA and stroke upon admission, and serially thereafter every day up to 7 days and every other day up to 20 days. We found that in TIA and stroke patients, peripheral adenosine levels were increased to a similar extent upon admission (TIA = 264 +/- 53 vs. stroke = 257 +/- 60 nM, p = ns), peaked on the day 2 for TIA (300 +/- 60) and on day 3 for stroke (289 +/- 43) patients, and steadily decreased towards the normal range, reached by all TIA patients by day 5 and by stroke patients by day 15. Stroke and TIA are associated with a rapid increase in circulating plasma adenosine concentration in man, detectable in peripheral vein. The adenosine surge likely mirrors an increased production from the ischemic brain, and it lasts days (for TIA) and weeks (for stroke) after the acute event.

Reduced heart rate variability in patients affected with Rett syndrome. A possible explanation for sudden death.

Incidence of sudden death in Rett syndrome is greater than that of the general population and cardiac electrical instability is a prime suspect cause. Our study shows that girls with Rett syndrome had significantly lower heart rate variability (marker of autonomic disarray) and longer corrected QT intervals compared with an age-matched group of healthy girls. These abnormalities increased with advancing stages of the syndrome. These findings suggest a possible role of cardiac dysfunction in the sudden death associated with Rett syndrome.

Pharmacological preconditioning of ischemic heart disease by low-dose dipyridamole.

Fourteen patients affected with coronary artery disease underwent two consecutive dipyridamole echocardiographic stress tests, in basal conditions and after repeated low doses of intravenous dipyridamole, following the observation that pulse increases in adenosine plasma levels due to repeated intravenous administration of dipyridamole mimic the mechanism of ischemic preconditioning. Echocardiographic, electrocardiographic, haemodynamic parameters, and adenosine plasma levels were measured. After the second test, six patients were completely negative, and in those eight still positive the onset of dyssynergy was delayed.

QTc interval prolongation during infusion with dipyridamole or adenosine.

The aim of our study was to discover whether there was a relationship between the QTc interval prolongation on the standard 12-lead electrocardiogram (ECG) and provoked myocardial ischemia. Since the increase of adenosine plasma levels, obtained either with adenosine or dipyridamole (an adenosine reuptake inhibitor) infusion, has been used to test the coronary artery reserve in patients affected by coronary artery disease, the QTc interval modifications during dipyridamole or adenosine echocardiographic stress test were evaluated. Twenty-five patients admitted to our Institute for evaluation of chest pain of suspected myocardial origin underwent an echocardiographic dipyridamole stress test (0.84 mg/kg over 10 min) after discontinuation of antianginal treatment. Of these patients, 10 underwent an echocardiographic adenosine stress test (scalar doses of 50, 75, 100, 140 micrograms/kg/min) after 48-72 h. The Bazett formula was used to evaluate the QTc interval. After dipyridamole and adenosine administration, a significant prolongation of the QTc interval was observed only in those patients who had positive test results. Our data suggested that QTc interval prolongation during pharmacological stress tests might be considered a marker of myocardial ischemia.

Calcium infusion induces myocardial ischaemia in patients with coronary artery disease by a mechanism possibly adenosine mediated.

In the first part of the study five healthy volunteers were submitted to i.v. infusion of 0.2 mM.kg-1 b.w. of calcium gluconate over 20 min. Total calcium (atomic absorption method), ionized calcium (ion-selective electrode method) and adenosine (HPLC technique) were measured at the following times: 0 (basal), 5, 10, 15, 20 (end of infusion), 25, 30, 35, and 50 min. The increase in total and ionized calcium serum levels was associated with a significant increase in adenosine plasma levels (from 207 +/- 41 to 362 +/- 63 nM.l-1, P < 0.001). Since the increase in adenosine plasma levels, obtained either with adenosine or dipyridamole (an adenosine reuptake inhibitor), has been used to test the coronary reserve in coronary artery disease (CAD) patients, in the second part of the study we compared the effects of calcium infusion with dipyridamole in 15 subjects. Pharmacological stress tests were evaluated by monitoring two-dimensional echocardiography and ECG. Ten patients had positive results with both the dipyridamole stress test and the calcium infusion. Our results show that calcium infusion induces an increase in adenosine plasma levels that can elicit a dipyridamole-like coronary steal, thus suggesting the central role of extracellular adenosine in myocardial ischaemia.