PubMed Health⌕ Search

Biomedical subjects

A Uncini

Publications and source records attributed to A Uncini.

At least 37 records · Page 2Linked to original sources
PubMed1999

Prednisone and plasma exchange improve suppressor cell function in chronic inflammatory demyelinating polyneuropathy.

We have recently demonstrated that ConA-induced suppressor cell function is defective in chronic inflammatory demyelinating polyneuropathy (CIDP). To assess whether this defect plays a role in disease activity and its reversal is important in recovery, we studied modifications of ConA-induced suppressor cell function induced by prednisone and plasma exchange in 20 patients with CIDP. We found a significant increase towards normal of ConA-induced suppressor cell function after treatment in concurrence with clinical improvement. Induction of suppression, presumably through favorable modifications of the cytokine network or other humoral mediators, might be one, among others, of the mechanisms through which prednisone and plasma exchange are effective in CIDP.

Adolescent↗
PubMed1999

Effect of rhTNF-alpha injection into rat sciatic nerve.

To assess whether TNF-alpha causes inflammatory demyelination or axonal degeneration, we injected into rat sciatic nerve saline, 100 U and 1000 U of rhTNF-alpha and studied the electrophysiological and pathological effects. At day 1 electrophysiology showed a slight reduction of proximal compound muscle action potential amplitude and pathology showed edema, inflammatory infiltration of vessel walls and endoneurium only in nerves injected with 1000 U of rhTNF-alpha. At day 5, there was no demyelination and a percentage of degenerated fibers similar in the three groups. To study the blood-nerve barrier, fluorescein isothiocyanate-labelled albumin was given intravenously after intraneural injection. The nerves injected with 1000 U rhTNF-alpha showed a leakage of the tracer in the endoneurium. TNF-alpha does not appear, at the doses used, to have myelinotoxic or axonopathic properties. The electrophysiological effect at day 1 may be due to mechanical compression of nerve fibers as a result of the blood-nerve barrier damage with consequent endoneurial edema.

Action Potentials↗
PubMed1999

Fisher syndrome with tetraparesis and antibody to GQ1b: evidence for motor nerve terminal block.

A Fisher syndrome (FS) patient with antibody to tetrasyaloganglioside GQ1b (GQ1b) developed late limb weakness. Serial motor conduction velocities (MCVs) showed a marked reduction of distal compound muscle action potential (CMAP) amplitudes, worse at 2-3 weeks, followed by a dramatic increase in week 5. Motor conduction velocities were always in the normal range, distal motor latencies changed only slightly, and conduction block in intermediate nerve segments was absent. These electrophysiological data might suggest an axonal neuropathy or a distal demyelinating conduction block. However, the dramatic increase of distal CMAP amplitudes over a short time without significant changes of distal motor latencies, CMAP duration, and morphology indicate that weakness in this FS patient might be due to a block of acetylcholine release from motor terminals, possibly mediated by anti-GQ1b antibodies.

Adult↗
PubMed1999

A relief maneuver in carpal tunnel syndrome.

We describe a maneuver that eases or abolishes paresthesias in carpal tunnel syndrome. With the affected hand palm up, the distal metacarpal heads are gently squeezed together; in some instances stretch of digits III and IV is also required. This maneuver may help in the clinical diagnosis of carpal tunnel syndrome, can be useful as a means of relieving symptoms, and provides the basis for the design of an innovative splint.

Adult↗
PubMed1999

Usefulness of segmental and comparative tests in the electrodiagnosis of carpal tunnel syndrome: the Italian multicenter study. Italian CTS Study Group.

The Italian CTS Study Group performed a wide multicentric and multiparametric study to quantify the increase of electrodiagnostic sensitivity using an extended neurophysiological protocol and particularly segmental and comparative tests. The study also evaluated the clinical features of carpal tunnel syndrome (CTS) diagnosed by these tests, using validated physician- and patient-oriented measurements. The study group was composed of 740 patients for a total of 1123 idiopathic CTS hands. Overall, the sensitivity of standard tests (median digit-wrist sensory conduction velocity and wrist-thenar distal motor latency) was 83.5%. Comparative/segmental tests disclosed abnormal findings in a further 11.4% of cases, providing CTS electrodiagnosis in about 7 of 10 "standard negative" cases. The overall sensitivity of the electrodiagnostic protocol was 94.9%. The CTS population diagnosed by segmental/comparative tests had a clinical picture characterized by a high percentage of pain, and severe discomfort but no limitation in functional daily activity. Our data confirm the usefulness of a complete neurophysiological assessment by using segmental/comparative tests when standard tests yield normal results.

Adult↗
PubMed1999

Chronic inflammatory demyelinating polyneuropathy in diabetics: motor conductions are important in the differential diagnosis with diabetic polyneuropathy.

OBJECTIVE: It is important to recognize CIDP occurring in diabetics because, unlike diabetic polyneuropathy, it is treatable. The aim of this study was to find out whether there are clues which help to differentiate CIDP in diabetics from diabetic polyneuropathy. METHODS: We compared the electrophysiological and pathological findings of 7 diabetics, who developed a predominantly motor polyneuropathy with the features of CIDP, with a group of diabetics referred for symptomatic polyneuropathy. RESULTS: Of the 7 diabetics we believe developed CIDP, 6 met at least 3 and one patient two of the 4 electrophysiological criteria of demyelination. Of the 100 patients referred for diabetic polyneuropathy, only 4 fulfilled two criteria and none 3. Nerve biopsy findings were not helpful in differential diagnosis, as segmental demyelination and remyelination, onion bulbs and inflammatory infiltrates, which are the histologic features of CIDP, were also present in diabetic polyneuropathy. CONCLUSIONS: CIDP can be diagnosed in a diabetic patient when motor symptoms are predominant, are more severe than expected in diabetic polyneuropathy and 3 of the 4 electrophysiological criteria for demyelination are fulfilled. When only two criteria are met, we believe that a trial with one of the established treatments for CIDP may be helpful in confirming the diagnosis.

Adult↗
PubMed1999

Minimal and asymptomatic chronic inflammatory demyelinating polyneuropathy.

OBJECTIVES: Show the chronic inflammatory demyelinating polyneuropathy (CIDP) is not only clinically heterogeneous but extremely variable in severity. METHODS: Three patients were referred for mild distal paresthesiae lasting more than 6 months and one for inguinal and thigh pain later ascribed to coxarthrosis. Strength was normal in all patients and tactile sensation reduced distally only in one. Tendon jerks were absent, except the knee jerks in one patient, reduced in lower limbs in two and normal in one. RESULTS: Electrophysiology showed a demyelinating neuropathy without motor conduction block. CSF protein content was increased in all patients. Nerve biopsies showed de-remyelination with varying degrees of axonal loss. Genetic studies excluded a demyelinating neuropathy associated with duplication or deletion of the 17p.11.2 segment. CONCLUSIONS: CIDP patients with pure sensory clinical presentation have been described but are generally more severely impaired. However, because of the mildness of symptoms and the unequivocal electrophysiological involvement of motor fibers, we think that in these cases the term minimal CIDP is more appropriate than sensory CIDP. These cases represent the most benign end of the CIDP spectrum. In our series minimal or even asymptomatic CIDP encompasses 8% of cases.

Adolescent↗
PubMed1999

Exclusive electrophysiological motor involvement in carpal tunnel syndrome.

OBJECTIVE: To define the frequency of exclusive electrophysiological motor involvement in carpal tunnel syndrome (CTS). METHODS: We reviewed the electrophysiological studies of 2727 consecutive hands with typical symptoms and signs of CTS and at least one abnormal test of the following: median distal motor latency (DML), digit two sensory conduction velocity (D2-SCV), segmental D2-SCV from wrist to palm, median-ulnar sensory latency difference from ring finger stimulation. RESULTS: Thirty-one hands (1.2%) had prolonged median DML ( > 4.4 ms) with normal SCV ( > 48 m/s). In 17 of 31 hands, segmental D2-SCV from wrist to palm or median-ulnar latency difference from ring finger stimulation were also performed with normal results in 8 hands, demonstrating a true exclusive electrophysiological motor involvement. CONCLUSIONS: In CTS, exclusive electrophysiological involvement of median motor fibers is rare. It may be related to preferential compression of the intraneural motor fascicles clumped superficially in the most volar-radial nerve quadrant or, more probably, to the fact that the recurrent thenar branch may exit the carpal tunnel through a separate ligamentous tunnel within the transverse carpal ligament where it may be preferentially or selectively compressed.

Carpal Tunnel Syndrome↗
PubMed1999

Haemostatic abnormalities, cardiac involvement and serum tumor necrosis factor levels in X-linked dystrophic patients.

Left ventricular thrombosis and systemic emboli have been demonstrated to complicate cardiomyopathy in Duchenne and Becker muscular dystrophy (DMD, BMD). We investigated plasma levels of prothrombin fragment 1+2 (F1+2). thrombin-antithrombin III complex (TAT) and circulating levels of tumor necrosis factor-alpha (TNF-alpha), a procoagulant cytokine that has been shown to be elevated in patients with depressed cardiac function, in 20 patients with DMD and 12 patients with BMD as compared with 30 age-matched control subjects. Significantly elevated levels of F1+2 (DMD: 1.4+/-0.8 nmol/l; BMD: 1.8+/-0.8 nmol/l vs. controls: 0.7+/-0.2 nmol/l, p <0.01 and p <0.001, respectively), TAT complexes (DMD: 4.7+/-2.7 microg/l, BMD: 5+/-2.3 microg/l vs. controls: 1.6+/-0.5 microg/l, p <0.001) and TNF-alpha (54+/-9 vs. 25+/-7 pg/ml, p <0.001) were observed in patients with the dystrophic disease compared to control subjects. A significantly negative correlation was also found between F1+2 and TAT complexes and left ventricular ejection fraction (r = -0.65, p <0.0001; r = -0.80, p < 0.0001, respectively) and a positive correlation between F1+2 and TAT complexes and serum TNF-alpha levels (r = 0.67, p <0.0001; r = 0.70, p <0.0001, respectively). Our results indicate a hypercoagulable state in X-linked dystrophic patients. A possible relationship between haemostatic activation, left ventricular dysfunction and TNF-alpha system upregulation may be suggested.

Adolescent↗
PubMed1998

Learning and approximation capabilities of adaptive spline activation function neural networks.

In this paper, we study the theoretical properties of a new kind of artificial neural network, which is able to adapt its activation functions by varying the control points of a Catmull-Rom cubic spline. Most of all, we are interested in generalization capability, and we can show that our architecture presents several advantages. First of all, it can be seen as a sub-optimal realization of the additive spline based model obtained by the reguralization theory. Besides, simulations confirm that the special learning mechanism allows to use in a very effective way the network's free parameters, keeping their total number at lower values than in networks with sigmoidal activation functions. Other notable properties are a shorter training time and a reduced hardware complexity, due to the surplus in the number of neurons.

Journal Article↗
PubMed1998

A late-onset mitochondrial myopathy is associated with a novel mitochondrial DNA (mtDNA) point mutation in the tRNA(Trp) gene.

We detected a novel pathogenic mutation, a G-->A transition at position 5521 of mitochondrial tRNA(Trp) gene, in association with familial late-onset mitochondrial myopathy. The mutation was detected in muscle but not in leukocytes from the family's proband. Morphological and biochemical studies documented a severe defect of muscle cytochrome c oxidase (COX) activity. RFLP analysis of single muscle fibers demonstrated segregation of higher percentages of mutated genomes in COX-negative ragged red fibres compared with normal fibers. A predominant impairment in synthesis of subunits I and III of complex IV due to their highest relative content of tryptophane might explain the greater susceptibility of complex IV to the pathogenic effect of this mutation. A progressive accumulation of mutated genomes in muscle can account for the late onset of symptoms observed in affected members.

Aged↗
PubMed1997

Acute motor axonal neuropathy with high titer IgG and IgA anti-GD1a antibodies following Campylobacter enteritis.

We describe the first two European cases of acute axonal motor neuropathy with both IgG and IgA anti-GD1a antibodies following Campylobacter enteritis. Both patients acutely developed severe weakness without sensory involvement, had antibodies to Campylobacter jejuni and polyclonal IgG and IgA titers > or = 12,800 to GD1a at onset, which decreased during follow-up. Serial electrophysiologic studies showed: 1, normal or only slightly slowed motor conductions; 2, evidence of a progressive loss of excitability and conduction failure in nerve fibers undergoing axonal degeneration in intermediate nerve segments and evidence of distal axonal involvement in one nerve; 3, normal sensory conductions, sensory potential amplitudes and somatosensory evoked potentials. Although we cannot exclude that axonal degeneration followed demyelination, we think that anti-GD1a antibodies account for the axonal involvement because GD1a is present in the axolemma and exposed at the node of Ranvier and in nerve terminals. The exclusive motor involvement could be explained by the fact that GD1a has a different internal structure in motor and sensory fibers.

Adult↗
PubMed1997

Low back pain due to hypertrophic roots as presenting symptom of CIDP.

Attention has recently been drawn to chronic inflammatory demyelinating polyneuropathy (CIDP) with symptomatic nerve root hypertrophy. A 31-year-old woman had fluctuating and worsening low back pain. Absent tendon jerks and a slight weakness of the hand interossei muscles suggested a diffuse neuropathy. The electrophysiological and histological findings were diagnostic for CIDP. Lumbar spine MRI showed marked nerve root enlargement with gadolinium enhancement. This case widens the range of the clinical presentations of CIDP. Further studies are warranted to ascertain whether cauda equina gadolinium enhancement may be a useful tool in the diagnosis of CIDP and a marker of disease activity for monitoring response to therapy.

Adult↗
PubMed1997

Conduction block and segmental velocities in carpal tunnel syndrome.

In carpal tunnel syndrome (CTS) standard measurement of median distal motor latency and sensory conduction does not distinguish whether low amplitude responses are due to axonal degeneration or demyelination. In 88 control and 294 CTS hands we recorded amplitude and duration of compound muscle action potential (CMAP) and of antidromic sensory nerve action potential (SNAP) after palm and wrist stimulation to determine wrist to palm amplitude, duration ratios and segmental conduction velocities. In 16% of CTS hands there was an abnormal amplitude reduction without increased duration of CMAP or SNAP from wrist stimulation indicating partial conduction block. In 148 hands distal motor latency to abductor pollicis brevis and/or sensory conduction to digit 2 were abnormal. In the remaining 146 hands wrist to palm motor conduction was less than 35 m/s in 22.6% and wrist to palm sensory conduction was less than 45 m/s in 13%. At least one segmental conduction was abnormal in 27% of hands. Segmental studies allow the discrimination between conduction block and axonal degeneration, increase diagnostic yield in CTS, and might be useful in addressing treatment and predicting outcome.

Action Potentials↗
PubMed1996

Benign monomelic amyotrophies of upper and lower limb are not associated to deletions of survival motor neuron gene.

Benign monomelic amyotrophies (BMAs) are rare conditions in which neurogenic atrophy is restricted either to the upper or lower limb. BMAs are usually sporadic, have insidious onset and slow progression followed by stabilization, are clinically confined for many years to a single limb and lack of sensory, bulbar, and pyramidal signs. Although the aetiology and pathogenesis of BMAs are unknown they are considered variants of spinal muscular atrophy with focal emphasis and a benign course. We studied 7 patients with BMAs to investigate whether they present alterations of the survival motor neuron gene (SMN) which has been found deleted or disrupted in proximal spinal muscular atrophy. All 7 patients showed the presence of both exon 7 and 8 of SMN gene. These findings indicate that deletions at the SMN locus are not present in BMA of upper and lower limb and suggest that these disorders are not only clinically but also genetically separate entities from proximal spinal muscular atrophies.

Adult↗