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Biomedical subjects

A Ghezzi

Publications and source records attributed to A Ghezzi.

At least 73 records · Page 4Linked to original sources
PubMed1992

Motor potentials of inferior orbicularis oculi muscle to transcranial magnetic stimulation. Comparison with responses to electrical peripheral stimulation of facial nerve.

Magnetic stimulation at the vertex evoked a motor potential (MP) in the inferior orbicularis oculi muscle of 10 healthy subjects with an onset latency of 8-13 msec. Its amplitude increased and its latency decreased when the muscle was contracted: the latency measured 9.5 +/- 1.3 msec with an intensity of stimulation 10-15% above threshold in the contracted muscle. This MP is secondary to excitation of the motor cortex. With the coil placed over the occipital scalp and the same stimulation intensity, an MP was recorded with an onset latency at 4.5 +/- 0.6 msec. This response reflects the activation of the facial nerve root. The peripheral electrical stimulation of the facial nerve at the mandible angle elicited an MP with an onset latency at 3.5 +/- 0.4 msec. Most records showed the presence of late components at about 30 msec for all types of stimulation.

Adolescent↗
PubMed1992

Perineal motor potentials to magnetic stimulation, pudendal evoked potentials and perineal reflex in women.

Motor potentials to transcranial and lumbar magnetic stimulation were recorded from the perineum in 14 healthy women. The response to transcranial stimulation presented an onset at 20.2 +/- 1.3 ms and a negative peak at 25.1 +/- 1.9 ms. Lumbar responses presented an onset at 5.1 +/- 0.8 ms, and the motor central conduction time measured 14.4 +/- 1.5 ms. Perineal reflex, cortical and lumbar pudendal evoked potentials were recorded after electrical stimulation of the labia minora. These tests are of possible clinical use in the evaluation of sphincter disturbances as they investigate the afferent and efferent pathways concerning pudendal nerve function.

Adult↗
PubMed1992

[Intestinal transit studied with radiopaque markers in patients with multiple sclerosis].

The patients affected with multiple sclerosis (MS) often complain of constipation. This symptom is little tolerated by the patient; its etiology is still unknown. MS patients often have their movements impaired by disease progress, so that they have to sit down for a long time, or else they exhibit severe problems walking or moving. MS patients also present low intraabdominal pressure during voluntary contraction of abdominal wall muscles. In these patients, the authors suggest to study intestinal transit time by means of radiopaque markers. To this purpose, the radiological follow-up contributes to the setting of colorectal MS dysfunctions by daily controls of the progress of per os radiopaque markers, focusing on colonic transit time and temporary deposit areas. The results show high incidence of anorectal constipation. Thus, the examination can be considered a useful tool in the study of MS dysfunctions and an effective alternative to anorectal manometry.

Colon↗
PubMed1991

Overview of azathioprine treatment in multiple sclerosis.

The efficacy of azathioprine in the treatment of multiple sclerosis was assessed by meta-analysis of the results of all published blind, randomised, controlled trials. 793 patients were enrolled in 5 double-blind and 2 single-blind studies. After 1 year of treatment, the increase in Kurtzke disability status score was no different in treated and control groups, but at 2 years there was a small difference (-0.22; 95% confidence interval [CI] -0.43, 0.003) in favour of azathioprine treatment; this difference was sustained, but not increased, after 3 years. The probability of freedom from any relapse during 1, 2, and 3 years' treatment was significantly greater in the azathioprine-treated group (relative odds over 3 years 1.97; 95% Cl 1.27, 3.04), but it is debatable whether the slight clinical benefits of azathioprine outweigh its side-effects.

Azathioprine↗
PubMed1991

CD4+ lymphocyte subsets in the cerebrospinal fluid of multiple sclerosis and non-inflammatory neurological diseases.

We studied paired cerebrospinal fluid (CSF) and peripheral blood (PB) samples from 18 inactive multiple sclerosis (MS) patients and 10 with non-inflammatory neurological diseases. By means of a dual-colour cytofluorimetric micromethod we were able to count 1500 cells on average in each CSF sample. We found a significant reduction of CD45RA+ and CD4+CD45RA+ cells in the CSF of MS patients. Similarly, CD45RA+ and CD4+CD45RA+ CSF/PB ratios were lower compared with controls. The reduction of suppressor-inducer T-cells did not correlate with CD8+ cell levels in the CSF. The CD4+ subset ratio (CD4+CD45RA-/CD4+CD45RA+) was significantly increased in the CSF of MS patients. Our data suggest that the reduction of CD4+CD45RA+ cells in the PB is not due to a segregation of such cells in the CSF. Conversely, CSF changes reflect changes in the PB similar to these found for other T-cell subsets.

Adult↗
PubMed1991

Pharmacodynamics of ticlopidine in man in relation to plasma and blood cell concentration.

In 6 normal volunteers given single oral doses of 250,500 and 1000 mg ticlopidine (T), the peak plasma level of unchanged drug was reached after about 2 h. There was no correlation between the plasma T level and its inhibitory effect on platelet function, expressed as % inhibition of ADP-induced aggregation. By means of HPLC and GC/MS significant concentrations of T were demonstrated in washed red cells, platelets and neutrophils, with a marked difference in the time course of the appearance of cell-associated drug. The time course of platelet-associated T very accurately fitted that of the antiaggregatory activity. After subacute oral administration (250 mg b.d. for 7 days), the maximum effect on platelet function was observed after 3 to 4 days, when a significant concentration of platelet-associated T had been reached. The pharmacological effect persisted as long as drug was detectable in platelet. An in vitro study strongly suggested that the antiaggregating effect was retained by treated washed platelets but not by treated plasma. It is suggested that the platelet compartment represents the pharmacological target of T via a specific uptake system.

Adult↗
PubMed1991

Study of central and peripheral motor conduction in normal subjects.

Motor potentials to transcranial and cervical magnetic stimulation and F-wave were recorded in 37 arms of 25 normal subjects. Clockwise and anticlockwise cervical stimulation were performed over C5, C7 and T2 spinous processes. A significant correlation was found between height and measurements of central and peripheral motor conduction. Peripheral motor conduction measured by F-wave derived techniques (Kimura formula) was 0.5 msec higher as compared with responses to cervical magnetic stimulation. The site and current flow direction of cervical magnetic stimulation influenced the amplitude of responses but not their latency: responses were larger in the right arm when the centre of the coil was placed over the C5 spinous process and clockwise stimuli were used. The same results were obtained in the left arm when the coil was reversed.

Adolescent↗
PubMed1991

Motor potentials of bulbocavernosus muscle after transcranial and lumbar magnetic stimulation: comparative study with bulbocavernosus reflex and pudendal evoked potentials.

Motor potentials of the bulbocavernosus muscle were recorded in 17 healthy subjects after transcranial and lumbar magnetic stimulation. The latencies (SD) were respectively: 22.9 (1.8) and 5.9 (0.4) ms. The central conduction time was 17.0 (2.5) ms. The bulbocavernosus reflex presented an onset at 34.5 (3.3) ms and a negative peak at 43.1 (3.9) ms. The cortical pudendal evoked potential was W shaped: the first peak had a latency of 35.4 (2.8) ms. The concurrent recording of motor potentials, bulbocavernosus reflex, pudendal evoked potentials gives a measure of peripheral and central, afferent and efferent neurological pathways related to pudendal nerve function.

Brain↗
PubMed1990

Decrease of CD4+CD45+ T-cells in chronic-progressive multiple sclerosis.

Circulating lymphocyte subpopulations defined by anti-CD45 and other more common T-cell-specific monoclonal antibodies were analysed in 77 patients with multiple sclerosis and 38 healthy controls. A selective decrease of CD4+CD45+ cell percentages and absolute numbers in chronic-progressive patients was found; in 13 out of 26 patients this subpopulation was less than 11% CD4+CD45+ cells. Similarly, the whole CD45+ cell subset, as well as CD45+ cells expressed as percentages of CD4+ cells, were significantly reduced in chronic-progressive multiple sclerosis. CD4+CD45+ cells, commonly termed "inducer of suppression" T-lymphocytes, did not correlate with percentages or numbers of CD8+ cells. It is concluded that suppressor inducer T-cells act on the CD8+ subset function rather than reducing CD8+ cell numbers. Since CD4+CD45+ cells represent an early stage of lymphocyte maturation (naive T-cells), an under-representation of this subpopulation in active multiple sclerosis might reflect an increased conversion of naive cells into memory cells. This concept may be relevant for a better understanding of the disease pathogenesis.

Adult↗
PubMed1990

Epilepsy in multiple sclerosis.

In a series of 2,353 multiple sclerosis (MS) patients, 40 subjects presented seizures, with an overall prevalence of 1.70%. The prevalence was 2.33% (34/1,459) in definite MS cases, 0.58 in probable cases (3/518), 0.79 in possible cases (3/376). Twenty-six patients were females, 14 were males. In 13 cases, epilepsy had begun before MS onset; in 4 patients, the two diseases started contemporarily; in 23 patients, epilepsy followed MS onset. No relationship was found between frequency of seizures and course of MS nor between frequency of seizures and MS severity. In 12 patients, magnetic resonance imaging was performed: plaques adjacent to the cerebral cortex were found in 3 cases. The electroencephalogram showed paroxysmal discharges in 11 patients (focal in 2, diffuse in 9). Slow theta and/or delta activity was found in 15 patients (focal in 7, diffuse in 6, both focal and diffuse in 2). The EEG was normal in 14 patients. Possible etiological factors other than MS were recognized in 4 patients only: cranial trauma in 3, meningitis in 1. Our study on a large MS population confirms that MS is associated to a risk for epilepsy higher than that of the general population.

Adolescent↗
PubMed1989

New in vivo model to assess venous endothelial cell functions. Effect of defibrotide.

In the past few years there has been increasing interest in the role of the vascular endothelium as an active modulator of biological responses. Endothelial cells exert antithrombotic activity by the release of prostacyclin [23] and adenine nucleotides [16], the availability on the cell surface of heparin-like substances [3], and thrombomodulin-mediated activation of protein C [8]. In addition, endothelium is involved in the regulation of fibrinolysis by releasing soluble factors, such as tissue plasminogen activator (tPA; [10]) and plasminogen activator inhibitor (PAI; [22, 11]), as well as in the control of vascular responsiveness by the production of smooth muscle relaxing and contracting factors. Endothelial cells have also been shown to synthesize and to express procoagulant activities [18]. Many data on endothelial cell functions has been obtained from two experimental models, namely endothelial cell cultures and perfused segments of animal and human vessels. Both are subject to methodological criticism since they only represent in part in vivo conditions, and the necessary experimental manipulations and laboratory procedures greatly modify the naturally occurring cellular functions. In order to overcome such difficulties as far as possible, a new in vivo model has been employed to provide easily assessable and reliable data on the properties of endothelial cells in man. A venous segment was isolated functionally by cannulating a dorsal vein in the hand and a cubital vein in the same arm. Changes observed ex vivo in blood from the cubital vein following infusion into the hand vein of an active drug, can mainly be attributed to its local effect on the venous wall. At the same time, a cubital vein in the other arm was cannulated in order to provide information to distinguish systemic from regional effects.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Two familial cases of Creutzfeldt-Jakob disease in Italy.

Two familial Italian cases of Creutzfeldt-Jakob disease are reported. Clinical picture and life history are presented and compared: 1) with the findings in familial cases reported in other countries, 2) with the findings (age at onset, disease duration) in sporadic Italian cases.

Adult↗
PubMed1989

Multimodality evoked potentials in amyotrophic lateral sclerosis.

Visual, brainstem auditory and somatosensory evoked potentials to medial nerve stimulation were recorded in 27 patients affected by amyotrophic lateral sclerosis. VEP N75, P100, N140, N75-P100 latencies and P100 amplitude, BAEP I-III, III-V and I-V interpeak-latencies were within normal limits in all ALS patients. Somatosensory evoked potentials were abnormally delayed in 8 patients: in 3 arms because of a delayed N9-N13 latency, in 9 arms because of a delayed N13-N19 latency.

Adult↗
PubMed1987

Azathioprine reduces intrathecal IgG synthesis in multiple sclerosis.

Intrathecal IgG synthesis and CSF oligoclonal bands were reexamined after 18-24 months in 66 patients with multiple sclerosis; 40 of them received azathioprine (AZA) 2.5 mg/Kg/die; all received a course of dexamethasone (DEXA) during clinical relapses. The IgG Index was significantly reduced in the group treated with AZA, especially in patients with short disease duration, low disability and high IgG index. Changes observed in CSF banding pattern were not significant. These results suggest an effect of AZA on IgG synthesis, as reported by in vitro studies.

Adult↗