A highly divergent mtDNA sequence in a Neandertal individual from Italy.
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Animals↗
Biomedical subjects
Stefano Ricci
Publications and source records attributed to Stefano Ricci.
Carotid artery stenting: first consensus document of the ICCS-SPREAD Joint Committee.
BACKGROUND AND PURPOSE: The prevention of stroke and the correct treatment of carotid artery stenosis represent today a major debate in cardiovascular medicine. Beside carotid endarterectomy, carotid angioplasty and stenting is becoming more widely performed for the treatment of severe carotid obstructive disease, and is now accepted as a less invasive technique that may provide an alternative for selected patients, particularly those with significant comorbidities. An Italian multidisciplinary task force, in which converged the most representative scientific societies involved in carotid treatment, was created to provide neurologists, radiologist, cardiologists, vascular surgeons, and all those involved in prevention and treatment of carotid disease with a simple, clear and updated evidence-based consensus document. SUMMARY OF REVIEW: This First Consensus Document of the ICCS (Italian Consensus Carotid Stenting)/SPREAD group addressed the main issues related to methodology, definition of symptomatic and asymptomatic carotid stenosis, indication and procedures for carotid artery stenting, including the use of devices for preventing procedural embolic complications. Special attention was paid to credentials and competency for physicians qualifications to perform vascular angioplasty and stent placement, including training, acceptable complication rates and certification. CONCLUSIONS: As any guideline or consensus statement, also this document is valid as long as the evidence on which it is based remains up-to-date. In such a fast-evolving field of medicine as the management of carotid stenosis, it is mandatory to stimulate a continuous and fruitful discussion among all the professionals involved in this very evolutionary field.
Carotid Artery Diseases↗
Previous use of aspirin and baseline stroke severity: an analysis of 17,850 patients in the International Stroke Trial.
BACKGROUND AND PURPOSE: Some studies suggest that taking aspirin regularly at the time of the onset of stroke reduces stroke severity. Other studies suggest the converse (ie, that previous aspirin therapy is associated with greater stroke severity). We sought to examine this question among the patients enrolled in the International Stroke Trial (IST). METHODS: Analysis of the associations of reported use of aspirin in the 3 days before randomization in IST with baseline stroke severity (as assessed by stroke clinical syndrome, predicted outcome at 6 months, and observed outcome at 6 months). We adjusted analyses for confounding factors. RESULTS: We excluded those patients who were first scanned after trial entry and were found to have an intracerebral hemorrhage as the cause of the stroke leading to randomization. We performed analyses for all treatment groups combined. For the 17,850 patients with ischemic stroke, data at baseline and follow-up were available for 100% and 99%, respectively. Among these patients, 3820 (21.4%) reported previous aspirin use. Previous aspirin use appeared, in univariate analyses, to be associated with greater baseline stroke severity, more severe stroke syndrome, and, in control subjects, worse observed outcome at 6 months. However, after adjustment, these associations were no longer significant. CONCLUSIONS: In this large prospective and complete data set, we found no evidence of any association of previous aspirin use with baseline stroke severity. The analyses suggest that previously reported positive and negative associations may well have been attributable to the play of chance in small samples, confounding or other biases, rather than a biological effect of aspirin.
Adult↗
A programmable real-time system for development and test of new ultrasound investigation methods.
In vitro and/or in vivo experimental tests represent a crucial phase in the development of new ultrasound (US) investigation methods for biomedical applications. Such tests frequently are made difficult by the lack of flexibility of general purpose instruments and commercial US machines typically available in research laboratories. This paper presents a novel, real-time development system specifically designed for US research purposes. Main features of the system are the limited dimensions (it is based on a single electronic board), the capability of transmitting arbitrary waveforms to two probes, of storing the received radio-frequency (RF) echo data in a file and/or of processing them in real-time according to programmable algorithms. As an example of application, results of simultaneous hemodynamic and mechanic investigations in human arteries are reported. However, the high system flexibility and portability make it suitable for a large class of US applications.
Biomedical Research↗
Accurate Doppler angle estimation for vector flow measurements.
Traditional Doppler methods measure only the axial component of the velocity vector. The lack of information on the beam-flow angle creates an ambiguity that can lead to large errors in velocity magnitude estimates. Different triangulation techniques so far have been proposed, which basically perform multiple measurements of the Doppler frequency shift originating from the same region. In this work, an original approach is introduced, in which two ultrasound beams with known relative orientation are directed toward the same vessel, but only one of them is committed to perform a Doppler measurement; the second (reference) beam has the specific task of detecting the beam-flow angle. The latter goal is obtained by accurately identifying the achievement of the target 900 reference-beam-to-flow angle through the inspection of the backscattered Doppler signal spectrum. In transverse flow conditions, in fact, such spectrum is expected to be centered on the zero frequency, and even small deviations from the desired 900 orientation cause noticeable losses of spectral symmetry. Validation of the new method has been performed through experimental tests, which show that the beam-flow angle can be estimated with high accuracy (rms errors lower than 1 degree), and repeatable velocity magnitude measurements are possible. A procedure for automatically tracking the desired orientation by the reference beam is also introduced and shown suitable for implementation in steerable linear array transducers.
Animals↗
Size determination of bacterial capsular oligosaccharides used to prepare conjugate vaccines against Neisseria meningitidis groups Y and W135.
The glycoconjugate vaccines against Neisseria meningitidis groups Y and W135 consist of pools of selected oligosaccharides conjugated to the protein carrier (CRM197). Consistent production of these vaccines requires control and thus determination of the average degree of polymerisation of the oligosaccharides used for conjugation. Acid hydrolysis generates group Y and W135 oligosaccharides with N-acetylneuraminic acid at the reducing end. A method, involving NaBH4 reduction and quantification of this terminal N-acetylneuraminic acid by use of high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) following acid hydrolysis (2M TFA), was developed. The average degree of polymerisation is calculated from the ratio of reduced N-acetylneuraminic acid to total N-acetylneuraminic acid. The assay was qualified by application to group C, Y and W135 oligosaccharide standards characterised by liquid chromatography, mass and NMR spectroscopy.
Carbohydrate Sequence↗
Effects of vitamin C and aspirin in ischemic stroke-related lipid peroxidation: results of the AVASAS (Aspirin Versus Ascorbic acid plus Aspirin in Stroke) Study.
A condition of oxidative stress is known to occur in ischemic stroke, the current therapeutic intervention of which is largely limited to thrombolysis. To assess the effect of vitamin C - in conjunction to aspirin - in ischemic stroke-related lipid peroxidation, we measured plasma levels of ascorbate, of 8,12-isoprostanes F2alpha-VI (8,12-iPF2alpha-VI) and activities and levels of a broad spectrum of antioxidant enzymes and micronutrients in stroke patients randomized to receive, from stroke onset and up to three months, either vitamin C (200 mg/day) plus aspirin (300 mg/day) or only aspirin (300 mg/day). By the end of the first week, patients treated with vitamin C plus aspirin had higher vitamin C levels (p = 0.02) and lower 8,12-iPF2alpha-VI levels (p = 0.01) than patients treated with aspirin alone. The significance was maintained for the increase of vitamin C after three months of therapy (p < 0.01). The clinical functional outcome for both groups of patients similarly ameliorated after three months of treatment. We conclude that vitamin C, at the dose of 200 mg/day and in conjunction with aspirin, significantly decreases ischemic stroke-related lipid peroxidation in humans. Further studies are warranted to clarify whether the use of vitamin C may add clinical long-term beneficial effects in patients with stroke.
Ascorbic Acid↗
Clinical validation of common carotid artery wall distension assessment based on multigate Doppler processing.
Mechanical properties of human large arteries result from the interaction between blood pressure, wall distensibility and shear stress. Both the arterial diameter changes through the cardiac cycle (distension) and blood flow velocities can be noninvasively investigated through Doppler ultrasound approaches. Recently, an integrated system processing in real-time all the echo signals produced along an M-line has been developed. This system has been so far demonstrated to be suitable for accurate hemodynamic studies through the detection of blood velocity profiles. This paper reports on the extension of its processing capabilities to the real-time measurement of arterial distension. Tissue motion estimation is based on a modified 2-D autocorrelation algorithm. A novel adaptive approach to track wall position over time using the sum of the high-pass filtered displacement waveform and the low-pass filtered wall position is described. By observing the blood velocity profile, a rapid and accurate positioning of the ultrasound probe and an inherent check on perpendicular observation are provided. First clinical results obtained by measuring the distension of common carotid arteries in a group of 41 volunteers are reported and measurements are validated against those provided by a dedicated wall-track reference system. Average measured distension and diameter were 499 +/- 188 microm and 6.90 +/- 0.66 mm and intraobserver intrasession reproducibility tests showed coefficients of variability of 8.5% and 5.9%, respectively. The agreement between the proposed system and the reference system, expressed as bias +/- 2 SD of the differences, was -34 +/- 141 microm for distension and 0.05 +/- 1.07 mm for diameter.
Adolescent↗
Results of an electronic mail survey on hormones and telangiectasias.
BACKGROUND: The relationship between the development of telangiectasias and hormonal intake has not been well studied and is empirically managed by phlebologists. OBJECTIVE: To understand the behavior of the international phlebologic community regarding the treatment of leg telangiectasia in patients taking oral contraceptives or receiving postmenopausal hormone replacement therapy. METHODS: Simple questions concerning the causal effects of hormones, their influence on treatment, and general behavior were asked by an electronic mail questionnaire sent to 131 phlebologists in my personal database. RESULTS: The 61 answers received show the existence of two opposite "parties" concerning the influence of hormones on telangiectasia: cause and treatment. CONCLUSION: Opposite opinions without any scientific basis underline the ignorance surrounding a subject that concerns 50% of our patients.
Contraceptives, Oral↗
Sacral-neuromodulation CT-guided.
PURPOSE: Sacral neuromodulation is a new treatment for refractory voiding disorders such as urge incontinence, urinary retention, frequency-urgency syndromes and faecal incontinence. The current approach to sacral nerve stimulation consists of a two-stage procedure. The first is a PNE test (Percutaneous Nerve Evaluation) by a provisional electrically stimulated spinal needle, placed percutaneously in the S3 foramina for four to ten days. If successful, the second stage, permanent implantation, is carried out. The PNE test is performed under fluoroscopic control using the palpable bony sacral foramina as referral points. This technique can show some limitations, such as operator Rx exposure, poor visualization of sacral foramina because of bowel gas artefacts or sacral malformation. In order to reduce these inconveniences and to improve efficiency of the test we tried an alternative technique. The purpose of our study was to test the use of CT as an alternative technique in order to evaluate its advantages and possible routine use. MATERIALS AND METHODS: We tested 30 patients with the PNE test under CT guidance (16 males and 14 females) suffering from serious pelvic disorders and not responding to the normal therapeutic regime. Twenty-seven patients showed relative anatomical integrity of the pelvis and the sacrum, the remaining 3 patients presented morphological anomalies of the sacral foramina. With the patient in the prone position the sacral foramina were identified with CT volumetric scanning using a spiral CT scanner equipped with a second console for the three-dimensional reconstructions. Having identified the location of the S3 foramina, a sterile field was prepared and the spinal needle introduced checking correct positioning with a CT control scan. An electrode was then inserted after having checked correct muscular contractile response and the precise position with a further CT scan. RESULTS: Thirty patients were subjected to PNE under CT guidance for a total of 38 centerings. Eight patients underwent the PNE procedure on both the S3 foramina. The sacral foramen was centred at the first attempt in 36 out of 38 cases. Two cases required several attempts to centre correctly the foramen. In 4 patients out of 30 a second electrode was implanted. In one patient who had a nonconsolidated sacral fracture, CT guidance enabled insertion of the electrode inside the only practicable foramen, a manoeuvre that would have been impossible with fluoroscopical guidance. Only once was the electrode placed in a wrong location but promptly repositioned after a CT control. During the whole trial period we had a positive response to the PNE test in 18 out of 30 patients (60%), a partial response in 4 out of 30 patients and a negative response in the remaining 8 patients. None of the patients who underwent the PNE test had infectious complications and the procedure was well tolerated by all. The procedure lasted about 45 minutes.
Adult↗
Validation of the Oxfordshire Community Stroke Project syndrome diagnosis derived from a standard symptom list in acute stroke.
BACKGROUND: The Oxfordshire Community Stroke Project (OCSP) classification allows distinction of stroke subtypes with different prognosis. OCSP classification inferred from clinical signs filled out on patient entry forms has been used to facilitate subgroup analysis in clinical trials. However, such procedure has not been validated against clinical diagnosis. In preparation for an acute stroke trial, we set out to perform such a validation. METHODS: An OCSP syndrome diagnosis of 194 acute stroke patients in four hospitals was made within 24 h using a standard list with neurological signs, to be filled out by a stroke physician or neurological resident on duty. This was compared with OCSP diagnosis within 2 days of stroke onset by a (blinded) stroke neurologist ("gold standard"). RESULTS: The proportion of the OCSP syndromes was quite similar between standard list and clinical judgement. Sensitivity, specificity, positive and negative predictive values were respectively: LACS: 0.76, 0.88, 0.72, 0.90; TACS: 0.63, 0.93, 0.62, 0.88; PACS: 0.62, 0.76, 0.63, 0.75; POCS: 0.50, 0.98, 0.60, 0.97. Kappa for agreement was 0.63 (LACS), 0.37 (PACS), 0.50 (TACS). Neuro-imaging falsified stroke subtype diagnosis in 40 cases (20.6%) diagnosed using the standard list, and 42 (21.6%) diagnosed by stroke neurologists. CONCLUSION: A standard list-derived stroke syndrome diagnosis may be used as a clinical test to make an OCSP syndrome diagnosis in acute stroke. The use of such list in acute stroke trials may facilitate uniformity in early stroke subtype diagnosis. However, to increase such uniformity, ancillary methods such as acute MRI should be evaluated.
Aged↗
New trial(s) on antiedema treatment in stroke?
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Adrenal Cortex Hormones↗
Glycerol for acute stroke: a Cochrane systematic review.
Brain oedema is a major cause of early death after stroke. Glycerol is a hyperosmolar agent that is claimed to reduce brain oedema. We sought to determine whether I. V. glycerol treatment in acute stroke, either ischaemic or haemorrhagic, influences death rates and functional outcome in the short or long term and whether the treatment is safe. The Cochrane Stroke Group Trials Register was searched, conference proceedings were screened and some trialists were personally contacted. We considered all completed, controlled, published and unpublished comparisons, evaluating clinical outcome, in which intravenous glycerol treatment was initiated within the first days after stroke onset. Death from all causes, functional outcome and adverse effects were analysed. Analysis of short term death for acute ischaemic and/or haemorrhagic stroke was possible in ten trials where 482 glycerol treated patients were compared with 463 control patients. Glycerol was associated with a non-significant reduction in the odds of death within the scheduled treatment period (OR 0.78, 95 % Confidence Intervals 0.58-1.06). Among patients with definite or probable ischaemic stroke, glycerol was associated with a significant reduction in the odds of death during the scheduled treatment period (odds ratio 0.65, 95 % CI 0.44-0.97). However, at the end of the scheduled follow up period there was no significant difference in the odds of death (odds ratio 0.98, 95 % CI 0.73-1.31). Functional outcome was reported in only two studies and there was a non-significant positive effect on outcome at the end of scheduled follow up (odds ratio 0.73, 95 % CI 0.37-1.42). Haemolysis seems to be the only relevant adverse effect of glycerol treatment. This systematic review suggests a favourable effect of glycerol treatment on short term survival in probable or definite ischaemic stroke, but the magnitude of the treatment effect may be minimal (as low as a 3 % reduction in odds). Because of the relatively small number of patients and because the trials have been performed in the pre-CT era, the results must be interpreted cautiously. The lack of evidence of benefit in long term survival does not support the routine or selective use of glycerol treatment in patients with acute stroke.
Chi-Square Distribution↗
Different measures for assessing stroke outcome: an analysis from the International Stroke Trial in Italy.
BACKGROUND AND PURPOSE: We sought to assess the relationship between 2 simple questions on recovery (question 1: do you feel that you have made a complete recovery from your stroke?) and dependency (question 2: do you require help from another person for everyday activities?) and the Barthel Index (BI) and Oxford Handicap Scale (OHS), as well as the relationship between BI and OHS, in a large number of Italian stroke survivors who participated in the International Stroke Trial (IST). METHODS: We used data from 2423 patients interviewed by telephone at 6 months after the event. The kappa statistic, sensitivity, and specificity were calculated for several comparisons. Internal consistency for BI was calculated. RESULTS: The reliability of the dependency question compared with BI=20 (kappa=0.93) and the reliability of the recovery question compared with OHS=0 (kappa=0.89) were good. Sensitivity of the dependency question in predicting whether patients scored BI >18 was 0.98; sensitivity of the recovery question in predicting whether patients scored OHS=0 was 0.99. The reliability of BI=20 compared with OHS <3 was good (kappa=0.87). Internal consistency of BI was very high (Cronbach's alpha=0.96). CONCLUSIONS: The 2 simple questions are a good means of evaluating outcome from a patient's view and of dichotomizing the stroke survivor in a time-effective and reliable way.
Acute Disease↗