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Biomedical subjects

L Parisi

Publications and source records attributed to L Parisi.

At least 37 records · Page 2Linked to original sources
PubMed1998

A case of myokymia-cramp syndrome successfully treated with gabapentin.

We report a case of "myokymia-cramp syndrome", a rare and benign disease consisting of muscular cramps in the upper and lower limbs associated with generalized myokymias. In our patient, cramps had been present since adolescence and had increased in frequency and duration during the last 3 years, occurring about 8 or 9 times a day. Cramps were mainly nocturnal and also precipitated by walking; a previous treatment with carbamazepine did not improve the symptoms. Gabapentin therapy proved to be very satisfactory in relieving muscular cramps with a relatively low dosage (600 mg/day) and without any remarkable side effects. The possible interpretation of the mechanism involved in gabapentin induced relief of cramps is discussed. Gabapentin should be considered as a safe alternative treatment for muscular cramps.

Acetates↗
PubMed1997

Microdialysis monitoring of extracellular glutamate combined with the simultaneous recording of evoked field potentials in hippocampal organotypic slice cultures.

These experiments combined extracellular electrophysiological multirecordings from hippocampal organotypic slice cultures with application of drugs to and sampling of extracellular fluid from a restricted region of the slice using a microdialysis probe. Glutamate (Glu) concentrations were monitored in 0.5 or 2 min microdialysis samples, while evoked field potentials responses (EvFPR) in the CA1 region of the hippocampus (stimulation in the CA3 area) were simultaneously recorded using a multi-electrodes array (Physiocard). Glu was assayed by capillary electrophoresis with laser-induced fluorescence detection combined with a continuous flow derivatization of dialysates. The performance of this combined approach was demonstrated by monitoring extracellular Glu concentrations and EvFPR after K+ induced depolarisation, Glu uptake blockade by trans-pyrrolidine-2,4-dicarboxylic acid (PDC), and electrical stimulation. Such an approach allows a global monitoring of the neuronal functioning with a fine time resolution (up to 30 s) on a simple in vitro brain slice model, to be used as a complement to conventional in vivo microdialysis studies.

Animals↗
PubMed1997

Electrophysiological assessment of visual function in IDDM patients.

Various electrophysiological tests have been employed to reveal functional abnormalities at different levels of the visual system in insulin-dependent diabetic (IDDM) patients. The aim of our work was to assess, with a comprehensive neurophysiological protocol evaluating the retinal, macular and visual pathways functions, whether and when such electrophysiological abnormalities do appear in IDDM patients free of any fluorangiographic sign of retinopathy with various disease duration. Flash-electroretinogram (ERG), oscillatory potentials (OPs), pattern-electroretinogram (PERG), and visual evoked potentials (VEPs) in basal condition and after photostress were assessed in 12 control subjects (C) and 42 aged-matched IDDM patients without clinical retinopathy (DR-) divided, on the basis of the disease duration, into 4 groups (1-5, 6-10, 11-15, 16-20 years). In addition another age-matched group of IDDM patients with a background retinopathy (DR+; n = 12; duration of disease 18 +/- 49 years) was evaluated. In all IDDM DR-patients PERG and VEP were significantly impaired. In addition, groups 11-15 and 16-20 years displayed impaired OPs. All electrophysiological parameters were further impaired in DR+ patients. In conclusion, retinal, macular and visual pathways functions are differently impaired in IDDM (DR-) patients with different disease duration. Electrophysiological impairment starts in the nervous conduction of the visual pathways with an early involvement, goes on in the innermost retinal layers and in the macula and ends in the middle and outer retinal layers.

Adult↗
PubMed1997

Sprouting and functional recovery in co-cultures between old and young hippocampal organotypic slices.

We developed a model of lesion of Schaffer collaterals in hippocampal organotypic slice cultures to analyse the capacity for sprouting and functional recovery expressed in young (one week old) and old (four week old) slice cultures. Slice cultures were sectioned at different ages of maturation in two separate half-slices and maintained in co-culture. Functional recovery was assessed by measuring synaptic responses elicited across the lesion seven days after the lesion and sprouting was evaluated by biocytin labeling of the regenerating fibers seen under the same conditions. Sprouting and functional recovery were found to be markedly reduced and delayed in old vs young cultures. Preparation of co-cultures between young CA3 and old CA1 half-slices resulted in a significant reduction in the capacity for sprouting and regeneration of the young CA3 neurons. Conversely, co-cultures prepared between old CA3 and young CA1 half-slices showed a markedly enhanced capacity for sprouting and functional recovery of old CA3 neurons. These results indicate that the age-dependent impairment in sprouting and regeneration expressed in cortical regions can be improved by and depends upon the presence of a favourable environment.

Animals↗
PubMed1997

Contribution of central neuropathy to postural instability in IDDM patients with peripheral neuropathy.

OBJECTIVE: To evaluate the contribution of central neuropathy on postural impairment observed in diabetic patients with peripheral neuropathy. RESEARCH DESIGN AND METHODS: Central sensory and motor nervous propagation, nerve conduction velocity, and static posturography were assessed in the following age-matched subjects: 7 IDDM patients with peripheral neuropathy (group DN), 18 IDDM patients without peripheral neuropathy (group D), and 31 control subjects (group C). Somatosensory-evoked potentials (SEPs) during tibial nerve stimulation were recorded, and the spine-to-scalp sensory central conduction time (SCCT) was evaluated. Motor-evoked potentials (MEPs) were recorded from leg muscles during magnetic transcranial brain stimulation, and the scalp-to-spine motor central conduction time (MCCT) was evaluated. The following posturographic parameters were calculated from the statokinesigram: trace length, trace surface, velocity of body sway with its standard deviation, and VFY (a parameter derived from the velocity variance and the anteroposterior mean position of the body). RESULTS: SCCT was significantly higher in the DN group than in the C and D groups (P < 0.001). MCCT was similar in all groups. Posturographic parameters were all significantly impaired in the DN group (P < 0.01). While posturographic parameters showed a direct relationship with some parameters of peripheral nerve conduction, no correlations were observed with SEP and MEP central conduction time. These results were also confirmed by logistic regression, which indicates peripheral neuropathy as the only implicating factor in postural instability (odds ratio 0.22, 95% CI 0.07-0.75) after data reduction by means of factor analysis. CONCLUSIONS: Although diabetic patients with peripheral neuropathy show a delay in central sensory conduction, postural instability may be fully explained by the presence of peripheral neuropathy.

Adult↗
PubMed1996

Pre-symptomatic neurological involvement in Behcet's disease: the diagnostic role of magnetic transcranial stimulation.

Twenty Behcet's disease (BD) patients with or without neurologic signs and symptoms were studied by means of magnetic transcranial stimulation. The most frequent abnormalities were an increase of motor evoked potential latency and a delay of central motor conduction time (CMCT). In 5 out of 9 BD patients with pyramidal signs central motor conduction changes were present. Furthermore, 2 out of 7 patients without neurologic signs and symptoms showed an increased threshold and a prolonged CMCT. The data obtained suggest that this technique is useful not only to confirm the neurologic impairment but also to reveal subclinical or pre-symptomatic central motor involvement in BD subjects.

Adolescent↗
PubMed1996

Protective activity of a murine monoclonal antibody against acute and chronic experimental infection with type IV group B streptococcus.

A murine IgM monoclonal antibody (MAb H11) was developed against the type polysaccharide capsular antigen of group B streptococcus (GBS), serotype IV, after intraperitoneal immunisation of BALB/c mice with heat-killed bacteria. MAb H11 reacted in immunodiffusion with the purified polysaccharide in both its sialylated and desialylated form, giving a line of identity, and opsonised type IV GBS strains in an in vitro assay. When administered at the time of intraperitoneal lethal challenge with homologous GBS, or 4 h earlier, MAb H11 protected 90% of the mice. Protection was still observed when MAb H11 was given 4 h after the challenge. This MAb was strongly effective in preventing septic arthritis induced by type IV GBS.

Acute Disease↗
PubMed1996

Multimodal evoked potentials in HIV-1-seropositive patients: relationship between the immune impairment and the neurophysiological function.

Multimodal evoked potentials (PRVEP, BAEP, mSEP) were recorded in 56 HIV-1 seropositive outpatients free from opportunistic CNS pathologies and/or overt HIV-1 encephalopathy. EPs were altered in 17 of 39 (43.6%) seropositive subjects without AIDS (group A) and in 13 of 17 (76.5%) patients with AIDS (group B). A high incidence of subclinical alterations (30.8%) were found in group A patients. Significant BAEP (I-III, III-V, I-V) interpeak latency and mSEP (N9-N13, N9-N20) conduction time prolongations were found in group A and B patients. PRVEP P100 was significantly prolonged only in group B. An inverse relationship between BAEP interpeak latencies and CD4 count was found. Our findings support the hypothesis of an important role of immunodepression in the development of neurophysiologic abnormalities, together with a preferential involvement of acoustic pathways, in the course of HIV-1 infection.

AIDS Dementia Complex↗
PubMed1996

Purification and biochemical characterization of a 65-kilodalton mannoprotein (MP65), a main target of anti-Candida cell-mediated immune responses in humans.

A 65 kDa-constituent (MP65) of a whole-cell mannoprotein (MP) fraction of Candida albicans was purified by immunoaffinity chromatography with monoclonal antibodies directed against periodate-insensitive, protease-sensitive MP epitopes, putatively polypeptide in nature. These antibodies were obtained by immunization of mice with concanavalin A bead-coupled, low-glycosylated MP from hyphal cells of C. albicans grown in the presence of a subinhibitory dose of tunicamycin. The immunoaffinity-purified MP65 molecule had a pI of 4.1 and a protein/polysaccharide ratio of 1.8:1. It was resistant to hydrolysis by endoglycosidase H, endoglycosidase F, or N-glycoffanases but still reactive with concanavalin A. The polysaccharide moiety of MP65 was composed exclusively of mannose and glucose at a ratio of 12.7 to 1. The protein moiety showed numerous potential O-glycosidic linkage sites as suggested by the high proportion of serine and threonine (together accounting for more than 20% of the total amino acid composition) and susceptibility to diluted alkali. This treatment and digestion with alpha-mannosidase caused a reduction in the MP65 molecular mass to around 54 kDa. The N-terminal sequence of MP65 protein moiety was rich in alanine and valine (7 of 13 amino acids) and did not show any significant homology with deposited sequences in data banks. Purified MP65, at doses of a few nanograms, induced extensive T-cell proliferation of human peripheral blood mononuclear cells. This proliferation was specifically inhibited, in a dose-response fashion, by the antigen-binding fragment of the monoclonal antibody used for immunoaffinity purification. Overall, these results highlight biochemical and molecular details of MP65, a main target of human T-cell response to C.albicans.

Amino Acid Sequence↗
PubMed1996

Postural rearrangement in IDDM patients with peripheral neuropathy.

OBJECTIVE: To evaluate the influence of diabetic peripheral neuropathy on postural strategy. RESEARCH DESIGN AND METHODS: Static posturography and nerve conduction velocity were performed in the following age-matched subjects: 10 IDDM patients with peripheral neuropathy, 23 IDDM patients without peripheral neuropathy, and 21 control subjects. All subjects with signs or symptoms of postural instability were excluded from the study. The following posturographic parameters were drawn: 1) velocity of body sway, expressed as mean velocity and average of the SDs, 2) VFY, the parameter derived from the velocity variance and the anteroposterior mean position of the body (this parameter monitors the postural strategy pursued by the subject), and 3) fast Fourier transformation on the x (FFTX) and y (FFTY) planes, spectral analysis of the frequencies of body oscillation on frontal (x) and anteroposterior (y) planes. RESULTS: Mean velocity and its SD were higher in IDDM patients with peripheral neuropathy than in control subjects and IDDM patients without peripheral neuropathy (P < 0.001). VFY was increased in IDDM patients with peripheral neuropathy versus control subjects and IDDM patients without peripheral neuropathy (P < 0.01). A direct relationship was found between parameters of posturography and some parameters of nerve conduction tests. CONCLUSIONS: Diabetic patients with peripheral neuropathy demonstrate a shift from physiological ankle control to hip postural control as monitored by specific posturography analysis.

Adult↗
PubMed1995

Electrophysiological assessment of visual function in newly-diagnosed IDDM patients.

Electrophysiological tests (electroretinogram, oscillatory potentials, visual evoked potentials, in the basal condition and after photostress) reveal an abnormal function of the visual system in insulin-dependent diabetic (IDDM) patients. The aim of our work was to assess whether electrophysiological abnormalities in visual function exist in newly-diagnosed diabetic patients free of any fluorangiographic signs of retinopathy. Ten control subjects (age 28.7 +/- 2.44 years) and then IDDM patients (age 25.2 +/- 6.78 years; disease duration 5.3 +/- 3.5 months) in stable metabolic control (HbA1C 7.5 +/- 1.1%) were evaluated. Flash-electroretinograms and oscillatory potentials were similar in both groups. Visual evoked potentials (VEP) recorded under basal conditions showed that P100 latency was significantly increased in the diabetic patients compared to control subjects (p < 0.01), while N75-P100 amplitude was similar in both groups. The recovery time of VEP after photostress was equivalent in diabetic patients and control subjects. The impaired basal VEPs suggest an early involvement of the nervous conduction in the optic nerve. However, the preserved flash-electroretinogram and the normal recovery time after photostress indicate that a short disease duration does not induce physiopathological changes in the outer retinal layers or in the macular function.

Adult↗
PubMed1995

Body sway in diabetic neuropathy.

OBJECTIVE: To evaluate the influence of peripheral neuropathy on body sway assessed by posturography. RESEARCH DESIGN AND METHODS: The age-matched study subjects included 10 insulin-dependent diabetes mellitus (IDDM) patients with peripheral neuropathy (DN), 23 IDDM patients without peripheral neuropathy (D) according to the San Antonio Consensus Conference guidelines, and 21 control subjects (C). All subjects with symptoms and/or clinical signs of postural instability were excluded from the study. RESULTS: The trace surface was significantly larger in the DN than in the C and D groups (P < 0.05), and the trace length was longer in the DN than in the C and D groups (P < 0.01). Mean velocity was faster in the DN than in the other two groups (P < 0.001). A direct relationship was found between the parameters of posturography and some parameters of the nerve conduction velocity. CONCLUSIONS: Diabetic patients with peripheral neuropathy demonstrate a relative deficit in their ability to maintain posture. Posturography allows an early disclosure of the failure of postural control.

Adult↗
PubMed1994

Visual evoked potentials after photostress in insulin-dependent diabetic patients with or without retinopathy.

Visual evoked potentials (VEPs) were assessed under basal conditions and after photostress in normal control subjects, in insulin-dependent diabetic patients with retinopathy (IDDPWR) and in insulin-dependent diabetic patients without retinopathy (IDDP). The VEPs recorded under basal conditions showed a P100 latency significantly higher in IDDP and IDDP-WR eyes than in control eyes and in IDDPWR than in IDDP eyes (P < 0.01). N75-P100 amplitude was significantly lower in IDDP and IDDPWR eyes than in control eyes (P < 0.01). No difference was recorded in the N75-P100 amplitudes between IDDP and IDDPWR eyes. In all eyes, the VEPs recorded after photostress showed an increase in latency and a decrease in amplitude. In both IDDPWR eyes and IDDP eyes VEPs recorded at 20, 40 and 60 s after photostress showed higher mean increments in P100 latency than in C control eyes, and IDDPWR eyes showed higher mean increments in P100 latency than IDDP eyes (IDDP vs control P < 0.01, IDDPWR vs control P < 0.01, IDDPWR vs IDDP P < 0.017). The mean reductions in amplitude observed at 20, 40 and 60 s after photostress in IDDP and IDDPWR eyes were lower than in control eyes (IDDP vs control P = 0.01, IDDPWR vs control P < 0.01, IDDPWR vs IDDP P < 0.01). VEPs were superimposable on the basal VEP (recovery time) at 73.9 s in control eyes, at 88.17 s in IDDP eyes and at 113.3 s in IDDPWR eyes. VEPs after photostress in IDDP patients with normal visual acuity and no fluorangiographic signs of retinopathy may show multiple modifications. This may indicate the presence of an early functional deficiency of the central retinal layers.

Adult↗
PubMed1993

Myopathy in long-term AZT therapy: clinical, electrophysiological and biopsy study in 67 HIV+ subjects.

The occurrence of muscular pathologies in AZT treated subjects has been evaluated in 67 HIV seropositive outpatients (56 AZT-treated and 11 untreated controls) in a neurological clinical and paraclinical follow-up study. Standard electromyographic and electrodiagnostic examinations, together with muscle enzyme determination, were performed in every subject, and periodically repeated at fixed intervals; in 11 patients a muscle biopsy sample was also obtained. An AZT-related myopathy was diagnosed in 8 biopsied cases; 9 more patients were considered to have AZT myopathy on clinical, EMG and ex juvantibus criteria. Statistical analysis showed that treatment duration was more relevant to the development of the myopathy than AZT dosage, though an individual predisposition could not be excluded, at least in a small number of cases. The risk of developing a toxic myopathy will therefore have to be considered when evaluating long-term effects of AZT therapy.

Adult↗