PubMed Health⌕ Search

Biomedical subjects

V Tugnoli

Publications and source records attributed to V Tugnoli.

At least 19 recordsLinked to original sources
PubMed1999

High-performance liquid chromatographic analysis of physiological amino acids in human brain tumors by pre-column derivatization with phenylisothiocyanate.

A reversed-phase high-performance liquid chromatographic technique for the determination of free amino acids in five biopsies of human brain tumors (two meningiomas, one glioblastoma and two oligodendrogliomas) is described. The frozen tissues were homogenized, deproteinized with perchloric acid and neutralized with potassium hydroxide. Aliquots of the supernatant containing the physiological amino acids are used for pre-column derivatization with phenylisothiocyanate. The derivatized PTC-amino acids (phenylthiocarbamyl derivatives) are stable for a five day period if stored as a powder at -20 degrees C in an inert atmosphere and they can be analyzed on a reversed-phase column (PicoTag) using a gradient of two eluents with absorption detection at a wavelength of 254 nm. Good resolution of several amino acids (>30) is achieved within ca. 60 min. For most amino acids this method is suitable for an accurate measurement over a wide range of physiological concentrations (50-400 pmol) starting from a very small amount of sample.

Amino Acids↗
PubMed1999

Hyperhidrosis and sympathetic skin response in chronic alcoholic patients.

Palmoplantar hyperhidrosis is frequently observed in patients with a clinical history of chronic abnormal alcoholic intake. It can be related to peripheral or central mechanisms such as abnormal spontaneous activity in peripheral damaged fibres; receptor hypersensitivity; compensatory incremented activity in segmentary anhidrosis; or impairment of central sweat control. With the aim of quantifying this phenomenon and of identifying its possible origin, sympathetic skin response (SSR) analysis was performed in 20 chronic alcoholic patients with clinical diffuse acral hyperhidrosis, compared with 30 normal subjects and 2 patients affected by primary palmoplantar hyperhidrosis (PPH). SSRs were recorded by disc electrodes place on the hands and feet, simultaneously. At the hand level two recording sites were selected: palm-dorsum proximally and ventral-dorsal tip of the third finger distally. Attention was paid to the number of SSR after a single endogenous or exogenous stimulus. The alcoholic patients were divided into two groups, with and without mild polyneuropathy. Both patient groups showed synchronous SSR at recording sites, with the same pattern and the normal delay between upper and lower arms. In the control group one response was generally related to a single stimulus; if more responses were elicited an evident adaptation was shown; in the two groups of patients an increase of the waves was observed in all the recording sites without any adaptation. The SSR profile described in alcoholic patients was observed also in PPH. The pattern of SSR waves in alcoholic patients seems to suggest a possible central origin of this type of hyperhidrosis.

Adolescent↗
PubMed1999

Neurological involvement in primary Sjögren's syndrome: clinical and instrumental evaluation in a cohort of Italian patients.

To evaluate nervous system involvement in a cohort of Italian patients with primary Sjögren's syndrome (pSS), 87 unselected patients (83 female, and four male) observed consecutively at our institution over a period of 5 years were screened by clinical and instrumental (MRI, SPECT, electrophysiological testing, CSF analysis) investigations for peripheral and central neurological abnormalities. Seroimmunological parameters and extraglandular features other than neurological manifestations were also evaluated. Seven patients had central nervous system (CNS) disease (8%), mostly non-focal dysfunction, and 12 had peripheral nervous system (PNS) disease (13.8%), mostly mild or severe sensory or sensory-motor polyneuropathies. One patient had concomitant CNS and PNS involvement. Compared with CNS disease, PNS involvement occurred in older patients (> 50 years), independent of the disease duration. Patients with and without neurological abnormalities did not differ for seroimmunological parameters (including antiphospholipid antibodies) or extraglandular manifestations. From a statistical point of view, the only relevant finding was the detection of a slight increase in serum IgA and IgM levels (p < 0.05) in patients with an intact nervous system. Neurological involvement in pSS, be it central or peripheral, is not a rare finding. A careful clinical neurological evaluation, combined with a multiplicity of instrumental investigations, is recommended in the global assessment of pSS patients.

Adult↗
PubMed1998

Different time courses of recovery after poisoning with botulinum neurotoxin serotypes A and E in humans.

Botulinum toxin serotypes A and E (BoNT/A and /E) cleave the carboxy-terminus of synaptosomal associated protein-25 (SNAP-25) removing nine and 26 residues, respectively. To investigate the effect of these lesions of the same target molecule, 11 volunteers were injected with 3 IU of BoNT/A in the extensor digitorum brevis (EDB) muscle of one foot and with 3 IU of BoNT/E in the contralateral one. In addition, seven volunteers were similarly injected with mixtures of BoNT/A + BoNT/E. Compound muscular action potential (CMAP) was measured at different time intervals and the percentage variation of CMAP (%CMAP) was calculated. Unexpectedly, a much faster recovery of %CMAP after BoNT/E injections was observed. Double poisoned EBD muscles recovered similarly to BoNT/E. So, a larger deletion of the SNAP-25 molecule caused by BoNT/E leads to a faster functional recovery.

Action Potentials↗
PubMed1998

On the action of botulinum neurotoxins A and E at cholinergic terminals.

Botulinum neurotoxins type A and E (BoNT/A and /E) are metalloproteases with a unique specificity for SNAP-25 (synaptosomal-associated protein of 25 kDa), an essential protein component of the neuroexocytotic machinery. It was proposed that this specificity is based on the recognition of a nine-residue sequence, termed SNARE motif, which is common to the other two SNARE proteins: VAMP (vesicle-associated membrane protein) and syntaxin, the only known substrates of the other six clostridial neurotoxins. Here we report on recent studies which provide evidence for the involvement of the SNARE motif present in SNAP-25 in its interaction with BoNT/A and /E by following the kinetics of proteolysis of SNAP-25 mutants deleted of SNARE motifs. We show that a single copy of the motif is sufficient for BoNT/A and /E to recognise SNAP-25. While the copy of the motif proximal to the cleavage site is clearly involved in recognition, in its absence, other more distant copies of the motif are able to support proteolysis. We also report on studies of poisoning human neuromuscular junctions with either BoNT/A or BoNT/E and describe the unexpected finding that the time of recovery of function after poisoning is much shorter in the case of type E with respect to type A intoxication. These data are discussed in terms of the different sites of action of the two toxins within SNAP-25.

Animals↗
PubMed1998

In vivo single voxel 1H MRS of glial brain tumors: correlation with tissue histology and in vitro MRS.

Eighteen patients affected by glial brain tumors were examined by localized single voxel magnetic resonance spectroscopy (1H MRS). For all patients histological diagnosis was obtained after stereotactic biopsy or surgical removal of the tumor. Histological nuclear atypia, tumor cellularity, necrosis, vascular proliferation and percentage of Ki-67 positive cells in the total cell populations were evaluated. It was found that some of the in vivo 1H MRS parameters were related to the histological features of the tumor. In particular, the Choi/Cri metabolite ratio obtained from the neoplastic tissues paralleled the Ki-67 cell proliferation index. For some of the patients 1H and 13C in vitro high resolution magnetic spectroscopy of surgical specimens was also carried out. 1H MRS of aqueous extracts from different biopsy specimens of the same tumor furnished fine biochemical information on intratumor heterogeneity. The degree of histological vascular proliferation of the tumor was correlated to the presence of cholesteryl esters in the 13C spectrum of the lipid fraction of surgical specimens.

Adult↗
PubMed1997

Botulinum neurotoxin serotype C: a novel effective botulinum toxin therapy in human.

Botulinum neurotoxin (BoNT) serotype A is commonly used in the treatment of focal dystonia. Nevertheless, some patients are or become resistant to this serotype. Consequently, other different serotypes have to be used. A comparison of the neuromuscular blockade induced by BoNT type A and C in the extensor digitorum brevis muscles of voluntary subjects was studied, by evaluating the amplitude variation over the time (until 90 days) of the compound muscular action potential elicited by supramaximal electrical stimulation of the peroneal nerve at the ankle. A very similar effect and temporal profile, was observed for each serotype. On this basis, two patients with idiopathic facial hemispasm and one with blepharospasm were treated with BoNT serotype C with very beneficial long lasting effects.

Adult↗
PubMed1997

The variability in the clinical effect induced by botulinum toxin type A: the role of muscle activity in humans.

When botulinum toxin (BT) is administered for the first time at fixed doses, variable clinical responses can be observed in patients with the same form of dystonic disorder. Many factors may contribute to this phenomenon, including the variability rate of absorption of the drug. Animal experimental models (rat diaphragm preparation) have demonstrated an increased absorption of BT in the terminal nerve endings of the muscle under repetitive electrical stimulation, suggesting that "muscle activity" also may play an important role. The aim of our study was to evaluate in humans the role of the muscle activity on the variability of the effect induced by BT type A. Eleven patients with blepharospasm and idiopathic facial hemispasm were studied by using neurophysiologic techniques. In nine patients, both extensor digitorum brevis (EDB) muscles were injected with low (3 IU), fixed doses of type A BT. For the first 24 h after administration of the drug, periodic electrical stimulation of only one EDB was used. The subsequent percentage changes in compound muscle action potential (CMAP) amplitude was calculated at different intervals over a 30-day period. The percentage in the CMAP for the stimulated EDB was compared with that of the contralateral nonstimulated side. We found that the effect of the induced neuromuscular blockade was significantly greater for the stimulated side. In the other two patients, we injected BT in one EDB and the same volume of normal saline solution in the contralateral muscle to assess the stability of the CMAP in untreated muscle over time. We observed that the CMAP was unchanged in the untreated EDB; therefore we concluded that muscle activity plays an important role in the variability of clinical response often seen.

Adult↗
PubMed1996

Botulinum neurotoxins: mechanism of action and therapeutic applications.

Recent studies have led to the discovery of the molecular lesions in motor neurons caused by botulinum neurotoxins. These neurotoxins are metalloproteinases that enter the cytosol and very specifically cleave protein components of the neuroexocytosis apparatus. Consequently, acetylcholine cannot be released and the muscle is paralysed. For this reason, botulinum neurotoxins are increasingly being used to treat a variety of conditions where a functional paralysis of neuromuscular junctions is useful as therapy.

Acetylcholine↗
PubMed1996

Botulinum toxin treatment in the facial muscles of humans: evidence of an action in untreated near muscles by peripheral local diffusion.

In a population of subjects with blepharospasm and facial hemispasm treated for the first time with botulinum toxin type A (BT) in the orbicularis oculi muscle, we performed an electrophysiologic study (compound muscle action potential and motor evoked potential) to assess whether BT effect could be detected in near untreated muscles (orbicularis oris and masseter). There was a significant BT action in nearly untreated muscles with different peripheral innervation that can be explained by local diffusion of the drug.

Action Potentials↗
PubMed1996

Cryoglobulinemic neuropathy related to hepatitis C virus infection. Clinical, laboratory and neurophysiological study.

Peripheral neuropathy is frequently reported in mixed cryoglobulinemia. As a close relationship has been established between mixed cryoglobulinemia and hepatitis C virus (HCV), the clinical, neurophysiological, and serologic findings of five patients affected by neuropathy, cryoglobulinemia and HCV infection were investigated. HCV infection was ascertained by the presence in the serum of anti-HCV antibodies detected by enzyme-linked immunosorbent assay(ELISA), and of HCV RNA assessed by polymerase chain reaction (PCR). Initial symptoms included paresthesias and painful dysesthesias in the legs. Later on, the patients developed a mainly asymmetric axonal polyneuropathy or a multifocal neuropathy associated with signs of systemic vasculitis. In this case series we report the short-term prognosis, as well as the response to interferon (IFN) alpha and conventional treatment. The presence of HCV RNA supports the hypothesis that a persistent HCV infection might be involved in the pathogenesis of mixed cryoglobulinemia and cryoglobulinemia-associated disorders.

Adult↗
PubMed1995

Sympathetic skin response in patients with Duchenne muscular dystrophy.

To verify an eventual disfunction of the palmar sympathetic skin activity in Duchenne Muscular Dystrophy, we studied the sympathetic skin response (SSR) with endogenous, Deep Breathing (DB-SSR), exogenous Startle (SE-SSR) and Electric type stimuli (EE-SSR) in a group of patients and a control group. At the same time as the SSR, the heart rate (HR) and the basic R-R interval variation (RRIV) as well as the EMG diaphragmatic activity were checked. In this way, significant differences in the latency (p = 0.02) and amplitude (p = 0.009) values of the EE-SSR and in the amplitude values of the SE-SSR (p = 0.001) and of the DB-SSR (p = 0.02) were noted in the DMD group compared to the control group. In the group of patients the rise in latency of the EE-SSR correlates with the age (p = 0.0001) and with the reduction of its amplitude (p = 0.03). This last parameter correlates with the stage of the illness (p = 0.02). In the control group the mean amplitude of the EE-SSR is approximately 30% greater than that of startle and 50% of deep breathing. Although with amplitudes homogeneously reduced, these ratios are also conserved in the DMD group. Moreover the HR is greater (p = 0.0001) whilst the RRIV is reduced (p = 0.02) in the group of the patients. However these parameters do not correlated either to the cardiac involvement or to the stage of the illness. The presence of the SSR for all the modalities of stimulation indicates the substantial integrity of the afferent and the efferent paths of the ANS. The alterations in latency and amplitude of the SSR in the patients could be the consequence of a lack of dystrophin at the level of the sudoriparous myopithelium in analogy to what has been demonstrated in the mdx mouse.

Adolescent↗