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A Cattaneo

Publications and source records attributed to A Cattaneo.

At least 19 recordsLinked to original sources
PubMed1995

Quick purification of recombinant human truncated tau proteins for immunoanalysis.

A simple and rapid purification method is described which exploits the heat stability of human tau (tau) protein to prepare truncated forms of this protein derived from bacteria. Bacterial cells expressing tau fragments were pelleted, resuspended in phosphate buffered saline and boiled for 5 min. After centrifugation the supernatant containing thermostable tau was filtered (0.45 microns) and used for immunoanalysis with monoclonal antibodies. The purified tau fragments exhibited identical antigenic properties as fragments isolated by a conventional procedure, based on ion exchange chromatography on phosphocellulose. In contrast to the conventional approach, our method is less complicated, cheaper and significantly reduces the time required for isolation of the recombinant tau fragments.

Antibodies, Monoclonal↗
PubMed1995

Neurofilament-negative neurones exhibit HVA Ca2+ currents with faster inactivation kinetics.

The whole cell configuration of the patch clamp technique was used to study the biophysical and pharmacological properties of voltage activated Ca2+ channel currents on hippocampal neurones cultured in the presence or absence of foetal calf serum. In the presence of serum cells were intensively immunostained with neurofilament (NF) antibodies. In the absence of serum, cells were non-immunoreactive; they were identified as neurones by their ability to generate action potentials. NF negative cells still expressed both high (HVA) and low (LVA) voltage activated Ca2+ channels. However, in comparison to NF positive neurones, HVA Ca2+ currents present in NF negative neurones had a faster inactivation kinetics.

Action Potentials↗
PubMed1995

Evaluation and retraining of adults' cognitive impairment: which role for virtual reality technology?

Immersive virtual reality (IVR) is a technology already developed to assist cognitive psychologists and therapists in their clinical work with brain-damaged patients. The rationale, the software and the hardware of the first application (ARCANA 1) based on affordable technology are discussed here, in order to provide a concrete example of what the authors think may be the role of IVR as a clinical tool. Although prospects are exciting, extensive research is needed to validate this new approach and reveal its limitations and advantages.

Adult↗
PubMed1995

Neuroantibodies: ectopic expression of a recombinant anti-substance P antibody in the central nervous system of transgenic mice.

Recombinant antibodies are efficiently secreted by cells of the nervous system. Thus, their local expression in the CNS of transgenic mice could be used to perturb the function of the corresponding antigen. As a first application of this approach, we have generated transgenic mice that express antibodies against the neuropeptide substance P, under the transcriptional control of the promoter of the neuronal gene vgf. The transgenic antibodies are expressed in a tissue-specific and developmentally regulated manner and are effective in competing with the endogenous substance P, as demonstrated by a marked inhibition of neurogenic inflammation and by motor deficits. This phenotypic knockout approach may provide a complementary alternative to gene knockout by homologous recombination.

Animals↗
PubMed1995

Identifying a putative common binding site shared by substance P receptor and an anti-substance P monoclonal antibody.

Substance P G-protein coupled receptor and the antigen recognition site of a monoclonal antibody raised against substance P share a stretch of five contiguous identical amino acids. This observation prompted us to build an atomic model of both the receptor and the antibody and to analyse their common features. In particular, we report here that a pocket of similar size and composition is present in both proteins, strongly suggesting a similarity in the mode of binding of both macromolecules to substance P. From the analysis of our models, the available data on the mode of binding of the antibody to substance P and recent data on substance P receptor mutants, we concluded that the pocket is very likely to be involved in binding of the C-terminal 'message sequence' of the tachykinin. This allowed us to suggest specific site-directed mutants of the receptor which should shed some light on the mechanism of peptide recognition by G-protein coupled receptors.

Amino Acid Sequence↗
PubMed1995

The use of phage display in neurobiology.

Phage display is a new technique that is used extensively in molecular biology to study protein-protein interaction, receptor- and antibody-binding sites, to produce monoclonal antibodies against diverse antigens, some of which are too well conserved for the production of monoclonal antibodies by traditional means, and to improve or modify the affinity of proteins for their binding partners. This technique could have many applications in neurobiology. This review describes the background to the technique, and illustrates a number of possible uses in neurobiology, ranging from the production of antibodies to non-immunogenic proteins and to those that are available as cloned DNA sequences only, to the detailed study of receptor-ligand interaction using either ligands, their receptors or neutralizing antibodies.

Antibodies, Monoclonal↗
PubMed1995

Idiopathic vulvodynia. Clinical evaluation of the pain threshold with acetic acid solutions.

Idiopathic vulvodynia is vulvar discomfort in which a diagnosis has not yet been established. As in other idiopathic pain syndromes, the involvement of primary afferent fibers (PAFs) has been postulated as playing a role in the pathogenesis and maintenance of idiopathic vulvodynia. Capsaicin induces the release of substance P (SP) by PAFs, producing vasodilation and increasing vascular permeability (neurogenic inflammation). Likewise, it has been shown that acid solutions can stimulate PAFs with the release of SP. To evaluate the pain threshold in women with idiopathic vulvodynia, 10 patients with vulvar pain but without significant vulvar physical changes and 10 asymptomatic controls received topically applied acetic acid solutions with increasing hydrogenionic concentrations (pH 3, 2.5, 2, 1.5, 1.2). Results related to pain threshold and pain time monitoring and intensity were analyzed with Fisher's exact and Wilcoxon's tests, respectively. Our data suggest that in idiopathic vulvodynia the pain threshold for acid solutions is decreased, probably in relation to increased sensitivity of PAFs involved in the transduction of painful signals.

Acetates↗
PubMed1994

Antibodies to nerve growth factor (NGF) prolong the sensitive period for monocular deprivation in the rat.

Neural plasticity in the visual cortex, as tested by changes in its functional organization induced by monocular deprivation (MD), is present only during a restricted period of postnatal development (critical period). To investigate whether this process of synapse strengthening depends upon NGF, we antagonized endogenous NGF during the critical period by implanting anti-NGF producing cells. Anti-NGF treated and control rats were monocularly deprived after the end of the critical period. In anti-NGF treated but not in control rats MD was still effective. We conclude that antagonism of endogenous NGF prolongs the critical period, possibly by delaying the process of synapse consolidation in the visual cortex.

Animals↗
PubMed1994

Intracellular immunization with cytosolic recombinant antibodies.

We report the application of a strategy to inactivate cellular proteins in vertebrate cells based on the intracellular expression of immunoglobulin genes. We have selected, in this instance, the p21 protein, encoded by the ras proto-oncogene, as a target protein. The variable regions of the neutralizing anti-p21ras monoclonal antibody Y13-259 were cloned in vectors for the expression of either the whole antibody molecule or its single-chain Fv fragment (ScFv) derivative. In order to target the recombinant antibodies to the cytosol, their hydrophobic leader sequence for secretion was mutated or deleted. When these proteins are expressed in the cytosol of Xenopus laevis oocytes they colocalize with the endogenous p21ras protein in the cytoplasmic face of the oocyte plasma membrane, and they markedly inhibit the H1 kinase activity induced by insulin. Moreover, cytosolic anti-p21ras ScFv fragments block the ensuing meiotic maturation. Thus the intracellular expression of both whole antibodies and antibody domains can be used to block a biological function.

Animals↗
PubMed1994

Plasma neuropeptide levels in psoriasis.

The immune system is important in the pathogenesis of psoriasis and emotional stress has precipitated psoriasis in many patients. Neuropeptides, alpha-Melanocyte stimulating hormone (alpha-MSH), beta-endorphin, met-enkephalin and substance P (SP) act as immunomodulators, and their secretion increases during periods of stress. To see whether these neuropeptides themselves might be related to psoriasis and/or to the aggressiveness of the disease, we evaluated the plasma neuropeptide levels in 13 patients with active psoriasis (patients with new lesions and/or pre-existing lesions that had become larger during the month before the study), in 11 patients with stable psoriasis and in 10 healthy controls. Plasma concentrations of neuropeptides were evaluated by RIA (immunoradiometric assay for beta-endorphin). Data were compared by the Student t-test for unpaired data. There were no significant differences between the plasma levels of any of the neuropeptides between active psoriatic patients and stable psoriatic patients, nor between the plasma levels of neuropeptides of psoriatic patients and those of control subjects. It seems unlikely that circulating neuropeptide levels are of primary importance in the manifestation of the psoriatic skin lesions.

Adult↗
PubMed1994

Topical calcipotriol for psoriasis--an immunohistologic study.

The aim of the present study was to investigate the distribution of Langerhans cells and T cells in the lesions and also the phenotypic expression of markers of activation on lesional T cells and keratinocytes, before and after 2 weeks of topical treatment of 7 psoriatic patients with calcipotriol. Before treatment, the infiltrate was composed mainly of T cells and there was decreased expression of CD1 on the intra-epidermal Langerhans cells. ICAM-1 and EGF receptor were present throughout the epidermis, but keratinocytes expressing Transferrin receptor were detected only in the basal layer. After 14 days of calcipotriol therapy, there were significantly fewer CD4T cells in the dermis and an increased number of intraepidermal CD1 + Langerhans cells. ICAM-1 expression on lesional keratinocytes was reduced in all patients, but the expression of EGF receptor was decreased in 3 patients only, and Transferrin receptor expression on keratinocytes had not changed. All these changes were concurrent with moderate clinical improvement of the lesions. The results suggest that in the early stages of the clinical response to calcipotriol there is an immunomodulating effect of the drug associated with variable decreases in keratinocyte expression of markers of activation.

Administration, Topical↗
PubMed1993

Single-channel properties of cloned cGMP-activated channels from retinal rods.

Single-channel properties of a cloned channel activated by cyclic GMP have been analysed. The mRNA encoding for the channel was injected into oocytes of Xenopus laevis and the current flowing through a single ionic channel activated by cGMP was studied in excised patches under voltage-clamp conditions. The ionic channel activated by cGMP had a single-channel conductance of 32 +/- 2 pS at +120 mV and 25 +/- 4 pS at -120 mV, and its conductance was not significantly affected by increasing the cGMP concentration from 20 microM to 200 microM. The single-channel currents in the presence of NH+4, Na+, K+, Li+ and Rb+ in the medium bathing the cytoplasmic side of the membrane at +140 mV were 5.3, 4.7, 3.8, 1.3 and 0.8 pA, respectively. The single-channel current in the presence of Cs+ was less than 0.5 pA. Ca2+ and Mg2+ (both 0.5 mM) in the presence of 100 microM cGMP did not appreciably affect the channel activity at membrane potentials more negative than -80 mV, whereas at +100 mV they reduced the single-channel conductance by about threefold. The ionic selectivity and the blockage by divalent cations of the native channel found in amphibian rods and in the cloned channel from bovine rods are quite similar. However, the cloned channel has well-resolved openings, especially at positive membrane voltages, whereas the native channel is characterized by a continuous flickering between the open and closed state.

Animals↗
PubMed1993

Use of living columns to select specific phage antibodies.

Here we demonstrate that it is possible to confront two recombinant microorganisms in order to select one using the other. We have shown that an epitope derived from p21ras expressed within the outer membrane protein, LamB, can be recognized both by the monoclonal antibody Y13-259, as well as the single chain Fv fragment derived from it. This specificity, which is maintained when the Y13-259 single chain Fv is expressed as a fusion protein with the phage fd gene 3 protein, has allowed us to use the living column of LamB-ras to purify Y13-259 phage from a background of non-binding phage, even at dilutions as high as 10 phage in 10(10) irrelevant phage.

Antibodies, Monoclonal↗
PubMed1992

Plasma alpha-melanocyte-stimulating hormone, beta-endorphin, met-enkephalin, and natural killer cell activity in vitiligo.

BACKGROUND: The immune system is important in the pathogenesis of vitiligo, and emotional stress has precipitated vitiligo in some patients. Opioid peptides, beta-endorphin, met-enkephalin, and alpha-melanocyte-stimulating hormone (MSH) act as immunomodulators, and their secretion increases during periods of stress. OBJECTIVE: To see whether these three neuropeptides might be related to vitiligo itself or to some alterations of the immune system in patients with vitiligo, we compared circadian variations in their plasma concentrations and natural killer cell activity of peripheral blood lymphocytes in 14 patients with vitiligo with those of 12 healthy subjects. METHODS: Plasma concentrations of neurohormones were evaluated by radioimmunoassay (immunoradiometric assay for beta-endorphin). Natural killer cell activity (NKCA) was assayed against K562 cells by 51Cr release technique. Data were compared by the Student t test and analyzed by cosinor analysis. RESULTS: The NKCA in vitiligo patients was higher than in controls but had similar circadian rhythm. alpha-MSH had no circadian rhythm in controls or in patients; plasma alpha-MSH levels were the same. Daily met-enkephalin and beta-endorphin oscillations in patients were no longer circadian. beta-Endorphin plasma levels in stable vitiligo were higher than in controls. There were no differences between patients with active vitiligo and normal subjects. Met-enkephalin plasma levels were generally higher in vitiligo patients, especially in the one with active vitiligo, than in controls. CONCLUSION: In vitiligo there are aberrations in neuropeptide, beta-endorphin, and met-enkephalin secretion. The plasma met-enkephalin level is positively correlated with the aggressiveness of the disease.

Adult↗
PubMed1992

[Solitary perforated diverticulum of the right colon. Five cases].

Solitary perforated diverticulum of the right colon is a very uncommon acute disease in emergency surgery, and usually a preoperative diagnosis of acute appendicitis is performed. Five cases of solitary perforated diverticulum of the right colon are presented. Preoperative diagnostic difficulties as well as surgical procedures are discussed.

Adult↗