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Biomedical subjects

L Murri

Publications and source records attributed to L Murri.

At least 73 records · Page 4Linked to original sources
PubMed1999

Vertebral and carotid artery dissection following chiropractic cervical manipulation.

A 50-year-old woman presented a sudden left occipital headache and a posterior circulation stroke after cervical manipulation for neck pain. Magnetic resonance imaging documented a left intracranial vertebral artery occlusive dissection associated with an ipsilateral internal carotid artery dissection with vessel stenosis in its prepetrous tract. This is the first reported case showing an associate vertebral and carotid artery dissection following cervical manipulation. Carotid dissection was asymptomatic and, therefore, its incidence may be underestimated. We emphasize that cervical manipulation should be performed only in patients without predisposing factors for artery dissection and after an appropriate diagnosis of neck pain.

Aortic Dissection↗
PubMed1999

The relationship of plasma catecholamine and lactate during anaerobic threshold exercise in mitochondrial myopathies.

Sympathetic system activation is considered one of the main factors influencing lactate production during exercise in normal individuals. In order to assess the role of such activation in mitochondrial myopathies, we compared blood catecholamine levels to those of lactate during an intermittent exercise performed at workloads near anaerobic lactate threshold. Following an initial increment, the patients (n = 10) exhibited a steady-state blood lactate shifted right relative to controls (n = 7), the peaks being respectively 665 +/- 29% and 322 +/- 11% of baseline. Plasma catecholamine increase in mitochondrial myopathies was 272 +/- 21% for norepinephrine and 261 +/- 18% for epinephrine, not statistically different from controls. Lactate/norepinephrine and lactate/epinephrine area ratios were significantly higher in the subjects than in controls (2.36 versus 1.48 and 2.40 versus 1.57, respectively). The study shows that the abnormal lactate production in mitochondrial myopathies is independent of the catecholaminergic response at the transition from aerobic to anaerobic exercise.

Adult↗
PubMed1999

Changes in long-latency reflexes onset latencies across full-wave rectified and non-rectified recordings.

Electrically elicited long-latency reflexes (LLRs) were obtained from thenar muscles by either fully rectified or non-rectified raw recordings in 10 healthy volunteers. The LLR II onset latencies were significantly (P < 0.0001) delayed on rectified (mean +/- SD: 49.8+/-2.9 ms) compared to raw (45.3+/-2.3 ms) recordings, with a mean difference of 4.4 ms. These data show that, according to the recording technique employed, the LLR II onset latencies can change considerably. The possible implications on cortical relay time (CRT) calculation and the understanding of the intracortical connections physiology are discussed.

Adult↗
PubMed1999

Epidemiology of dystrophinopathies in North-West Tuscany: a molecular genetics-based revisitation.

A molecular genetics-based epidemiological investigation was carried out in 1997 in the territory of North-West Tuscany, central Italy, to calculate incidence and prevalence rates of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Results were compared with a previous epidemiological study conducted in the same area in 1981, in the pre-dystrophin era. Routine adoption of methods of molecular diagnosis determined an increase in prevalence of BMD from 1.06 x 10(-5) to 2.42 x 10(-5) inhabitants, while cumulative incidence of DMD was markedly decreased from 23.12 x 10(-5) during the period 1965-1976 to 10.71 x 10(-5) male live births during the period 1977 1994. The combined reduction of DMD/BMD diagnostic error rate and familial recurrence could explain these results, providing the bases for a consistent redefinition of dystrophinopathy carrier frequency in the area considered.

Dystrophin↗
PubMed1999

Word recall correlates with sleep cycles in elderly subjects.

Morning recall of words presented before sleep was studied in relation to intervening night sleep measures in elderly subjects. Night sleep of 30 elderly subjects aged 61-75 years was recorded. Before sleep, subjects were presented with a list of paired non-related words and cued recall was asked immediately after the morning awakening. Recall positively correlated with average duration of NREM/REM cycles, and with the proportion of time spent in cycles (TCT) over total sleep time (TST). No significant correlations were found with other sleep or wake measures. These results suggest the importance of sleep structure for sleep-related memory processes in elderly adults.

Aged↗
PubMed1999

Impaired ascendant central pathways conduction in impotent diabetic subjects.

OBJECTIVES: Diabetic impotence is generally due to peripheral neuropathy, but a central pathway impairment has also been suggested. We evaluated somatosensory transmission in a group of impotent diabetic men to assess the role of central nervous system (CNS) involvement. MATERIALS AND METHODS: Somatosensory evoked potentials (SEPs) of pudendal (pdn) and posterior tibial (ptn) nerves were recorded in 74 patients. Type and duration of diabetes, severity of sexual dysfunction, medium term metabolic control, occurrence of microangiopathic chronic complications and autonomic neuropathy were evaluated. RESULTS: Our data show an impairment of central conduction times in pdn (25.7%) and ptn (39.2%) greater than peripheral nervous impairment (pdn 12.2%, ptn 8.1%), in impotent diabetic patients without any further major complication. Central nervous conduction delay resulted to be correlated with poor glycemic control. Significant evident autonomic dysfunction was found only in a minority of cases. CONCLUSION: Our data might suggest that altered conduction along CNS and somatic peripheral neuropathy might develop independently. We confirm the hypothesis of a "central diabetic neuropathy" and suggest that central sensory pathways involvement, not related to peripheral impairment, could play a role in the pathogenesis of erectile dysfunction in diabetic patients.

Adult↗
PubMed1999

Effect of 1-year treatment with interferon-beta1b on thyroid function and autoimmunity in patients with multiple sclerosis.

OBJECTIVE: Interferon-beta (IFN-beta) is a widely used therapy for multiple sclerosis (MS), a demyelinating disease of the central nervous system. This study has evaluated the effect on thyroid function and autoimmunity of a 1-year treatment with IFN-beta1b in patients with MS. PATIENTS: We studied 31 patients (age 34+/-7 years, 21 women) with relapsing-remitting MS during IFN-beta1b treatment of 1 year duration. Systematic thyroid assessment and measurements of serum interleukin-6 (IL-6) levels were performed at baseline and every 3 months during treatment. RESULTS: Sixteen percent of the patients had autoimmune thyroiditis before IFN-beta1b, all positive for anti-peroxidase antibodies. The overall incidence of thyroid dysfunction was 33% over 1 year (10% hyperthyroidism, 23% hypothyroidism). Thyroid autoimmunity developed in 5/26 patients (19%), in one case without dysfunction. In addition to autoantibody positivity at baseline, female gender and the presence of an ultrasound thyroid pattern suggestive of thyroiditis were identified by multiple logistic regression as additional risk predictors for the development of thyroid dysfunction. During IFN-beta1b treatment, serum IL-6 levels rose in a consistent biphasic pattern; there was, however, no difference between patients with or without incident thyroid abnormalities. CONCLUSIONS: We conclude that IFN-beta1b therapy can induce multiple alterations in thyroid function, some of which are unrelated to thyroid autoimmunity. IL-6 measurement is not useful to identify patients prone to develop thyroid abnormalities. Though thyroid dysfunction is generally subclinical and often transient, systematic thyroid assessment should be performed during IFN-beta1b treatment.

Adjuvants, Immunologic↗
PubMed1999

[High-intensity transcranial Doppler signals in patients wearing heart valve prostheses: a prospective study].

BACKGROUND: Transcranial Doppler sonography (TCD) of the middle cerebral arteries in patients with prosthetic heart valves reveals high-intensity transient signals (HITS) and can detect asymptomatic cerebrovascular microemboli. Both the nature of the underlying embolic material (either gaseous or corpuscular) and its clinical significance remain uncertain. METHODS: Seventy-one patients undergoing heart valve replacement (n = 63) or repair (n = 8) from June 1996 to June 1998 were prospectively evaluated preoperatively and one week, 3 months and 12 months after valve replacement using TCD. At each follow-up interval, clinical assessment was aimed at detecting neurological events. Furthermore, continuous echo-Doppler study of the carotid arteries and TCD of the middle cerebral arteries for a 30-minute period during each following visit was carried out. RESULTS: No HITS were recorded preoperatively in any patient. At one week, HITS were detected in 25 patients (35%): 22 (65%) of these had received a mechanical prosthesis and three (10%) a bioprosthesis. No HITS were recorded in patients with mitral repair. HITS were subsequently detected only in patients with mechanical prosthesis with a positive TCD at one week, the mean number of HITS per patient being 7 +/- 18 at 3 months and 8 +/- 24 at 12 months. No neurological symptoms were evident in any patients during the postoperative evaluation. Multivariate analysis showed mechanical prosthetic valve to be the only independent predictive risk factor for HITS development. CONCLUSIONS: The role of a mechanical prosthetic valve as a risk factor in the pathogenesis of HITS appears evident. However, HITS appear to be unrelated to possible postoperative neurological events. TCD could have more specific clinical applications if associated with methods that would make it possible to ascertain the nature of various embolic materials.

Aged↗
PubMed1999

Sleep stages preceding spontaneous awakenings in the elderly.

Spontaneous awakenings from sleep were studied in a group of 21 elderly subjects (mean age 69.29+/-3.02 years) free of neurological and somatic diseases. The prevalence of awakenings and the duration of waking bouts were analyzed with regard to the prior sleep state. The results showed an increased frequency of awakenings during Stage 2 NREM in the elderly, who wake out of Stage 2 NREM no less frequently than out of REM sleep. This trend is different from that observed in younger subjects (babies and young adults), where a clear prevalence of REM sleep awakenings has been reported. The duration of Stage 2 interrupted by awakening was shorter than Stage 2 followed by sleep. The duration of waking bouts did not differ according to the preceding sleep stage. It is suggested that the relative inability to sustain Stage 2 may be a mechanism which contributes to the difficulty of sleep maintenance in the elderly.

Aged↗
PubMed1998

T-cell interleukin-6 receptor binding in patients with myasthenia gravis.

Myasthenia gravis (MG) is a T-cell-dependent and antibody-mediated autoimmune disease of the neuromuscular junction, in which the cytokine network may be deranged. Specific receptors for interleukin (IL)-6, a cytokine with several effects on the neuroimmune system, have been found on human lymphocytes. The aim of the present study has been to assay IL-6 binding on peripheral blood T cells from MG patients. We found that T cells from MG patients have significantly more IL-6 receptors than those from controls (Bmax: 334 +/- 6 vs 251 +/- 4 (mean +/- SEM) receptors/cell). Such IL-6 binding sites are of the same type in patients and healthy subjects (Kd: 26.5 +/- 0.7 vs 25.7 +/- 0.9 (mean +/- SEM) pM). The enhanced T-cell interleukin-6 binding is due to an increased number of interleukin-6 receptors on T-helper lymphocytes. These results are discussed in terms of MG immunopathogenesis, since it has been reported that activated T cells have increased amounts of IL-6 receptors.

Adult↗
PubMed1998

Bilateral medial frontal infarction in a case of azygous anterior cerebral artery stenosis.

We describe the unusual case of a 63-year-old woman with a history of arterial hypertension who presented a sudden weakness of the lower limbs followed by mutism, akinesia and dyspraxia. Magnetic resonance images showed a bilateral medial frontal infarction. Digital subtraction angiography documented a right azygous anterior cerebral artery with severe stenosis in its sub-callosal tract; the left anterior cerebral artery showed mild hypoplasia with only sub-frontal and fronto-polar branches. No embolic source was documented. Afterwards the patient presented a gradual and partial recovery of both motor and cognitive functions.

Angiography, Digital Subtraction↗
PubMed1998

Slow wave sleep (SWS) distribution across night sleep episode in the elderly.

Slow wave sleep (SWS) distribution across night sleep was shown to be different between infants and young adults. The present research aimed at studying the SWS distribution across night sleep in elderly subjects. Nine healthy elderly subjects, 61-71 years old, were submitted to nocturnal polygraphic sleep recording. Eleven young subjects, 21-23 years old, were the control group. Recordings were visually analyzed according to Rechtschaffen and Kales rules; the method proposed by Webb and Dreblow was used for scoring SWS. An NREM-REM cycle was defined as a sequence of NREM and REM sleep not interrupted by a waking period longer than 15 minutes. SWS percentage was calculated for each successive NREM episode. No significant association between SWS percentage and cycle rank was shown in elderly subjects, whereas a significant association was observed in the young ones. This kind of SWS distribution could be interpreted as reflecting the restructuring of internal organization of sleep in the elderly.

Adult↗
PubMed1998

A simple method for the quantitative description of sleep microstructure.

A simple method for the quantitative description of sleep microstructure is proposed. This method is based on the computation of descriptors which provide a normalized measure of how the amplitude of the activity in a frequency band differs, at a given instant, from its background. The use of these descriptors makes it possible to identify epochs of transient increase in band activity, to measure their length, and to measure the time distance between two successive epochs.

Adult↗
PubMed1998

Evaluation of acute ischemic stroke using quantitative EEG: a comparison with conventional EEG and CT scan.

The sensitivity of quantitative electroencephalogram (EEG) was compared with that of conventional EEG in patients with acute ischaemic stroke. In addition, a correlation between quantitative EEG data and computerized tomography (CT) scan findings was carried out for all the areas of lesion in order to reassess the actual role of EEG in the evaluation of stroke. Sixty-five patients were tested with conventional and quantitative EEG within 24 h from the onset of neurological symptoms, whereas CT scan was performed within 4 days from the onset of stroke. EEG was recorded from 19 electrodes placed upon the scalp according to the International 10-20 System. Spectral analysis was carried out on 30 artefact-free 4-sec epochs. For each channel absolute and relative power were calculated for the delta, theta, alpha and beta frequency bands and such data were successively represented in colour-coded maps. Ten patients with extensive lesions documented by CT scan were excluded. The results indicated that conventional EEG revealed abnormalities in 40 of 55 cases, while EEG mapping showed abnormalities in 46 of 55 cases: it showed focal abnormalities in five cases and nonfocal abnormalities in one of six cases which had appeared to be normal according to visual inspection of EEG. In a further 11 cases, where the conventional EEG revealed abnormalities in one hemisphere, the quantitative EEG and maps allowed to further localize abnormal activity in a more localized way. The sensitivity of both methods was higher for frontocentral, temporal and parieto-occipital cortical-subcortical infarctions than for basal ganglia and internal capsule lesions; however, quantitative EEG was more efficient for all areas of lesion in detecting cases that had appeared normal by visual inspection and was clearly superior in revealing focal abnormalities. When we considered the electrode related to which the maximum power of the delta frequency band is recorded, a fairly close correlation was found between the localization of the maximum delta power and the position of lesions documented by CT scan for all areas of lesion excepting those located in the striatocapsular area.

Acute Disease↗
PubMed1998

Factor V Leiden mutation in a case with ischemic stroke: which relationship? A case report.

A 50-year-old man presented spontaneous internal carotid artery dissection with ischemic stroke. He had a history of deep venous thrombosis, and an activated protein C resistance due to factor V Leiden mutation was documented. He showed no other vascular risk factor. This unusual case puts the question whether this coagulation defect may be related to the stroke occurrence.

Aortic Dissection↗
PubMed1997

Changes in pain perception and pain-related somatosensory evoked potentials in humans produced by exposure to oscillating magnetic fields.

Nociception has been reported to be influenced by exposure to magnetic fields (MFs). The aim of this study was to investigate the effects of 2 h exposure to weak, oscillating MFs on pain perception thresholds and on pain-related somatosensory evoked potentials (SEPs). In 11 healthy volunteers, pain perception thresholds and pain-related SEPs were assessed by intracutaneous electrical stimulation. After sham treatment, pain thresholds significantly increased, whereas after MFs a slight non-significant decrease in thresholds was found. After both treatments pain-related SEP amplitude was reduced, but this decrease was more evident and statistically significant only after MF exposure. The increase found in thresholds after sham exposure may be due to stress-induced analgesia (SIA) and the contrasting behaviour recorded after MF exposure might indicate a suppression of SIA. The significant reduction in pain-related SEP amplitude observed after MF exposure provides the first evidence that human SEPs are influenced by MFs.

Adult↗
PubMed1997

Mitochondrial tRNA(Cys) gene mutation (A5814G): a second family with mitochondrial encephalopathy.

We report an Italian family with maternally inherited encephalomyopathy including progressive external ophthalmoplegia, seizures, and neurophysiological evidence of brainstem dysfunction. Mitochondrial DNA analysis showed a heteroplasmic point mutation at position 5814 in the tRNA gene for cysteine (A5814G), previously reported in a 5-year-old girl of Portuguese origin. The mutation was very abundant (> 95%) in both muscle and blood from the proposita and was present in lower proportions (average 85 +/- 6%) in blood from three less severely affected maternal relatives. This observation confirms pathogenicity for the A5814G mutation.

Adult↗