Biomedical subjects

A Berti

Publications and source records attributed to A Berti.

At least 37 records · Page 2Linked to original sources

PubMed1996

Seventeen copies of the human 37 kDa laminin receptor precursor/p40 ribosome-associated protein gene are processed pseudogenes arisen from retropositional events.

A cDNA coding for a 37 kDa polypeptide has been identified in several species as both the potential precursor of the 67 kDa laminin receptor (37LRP) and a putative ribosome-associated protein (p40). Interestingly, increased expression of this polypeptide (37LRP/p40) is consistently observed in invasive and metastatic cancer cells and is associated with poor prognosis. Southern-blot analysis of human genomic DNA predicted multiple copies of the 37LRP/p40 gene. In this study, we report that the number of copies of this sequence in the human genome is 26 +/- 2. We have sequenced and analyzed 19 genomic clones corresponding to the 37LRP/p40 gene and found that they were all processed pseudogenes. They all lack intronic sequences and show multiple genetic alterations leading in some cases to the appearance of stop codons. Moreover, they all bear characteristic features of retroposons as the presence of a poly(A)-tail at their 3' end and short direct repeated flanking DNA sequences. None of the pseudogenes analyzed present cis-elements in their 5' flanking region such as TATA or GC boxes. Our date reveal that over 50% of the 37LRP/p40 gene copies are pseudogenes most probably generated by retropositional events. The finding of multiple pseudogenes for the 37LRP/p40 suggests that the accumulation of several copies of this gene might have given a survival advantage to the cell in the course of evolution.

Base Sequence↗

PubMed1996

pp60v-src phosphorylates and activates low molecular weight phosphotyrosine-protein phosphatase.

Low M(r) phosphotyrosine-protein phosphatase belongs to the non-receptor cytosolic phosphotyrosine-protein phosphatase subfamily. It has been demonstrated that this enzyme dephosphorylates receptor tyrosine kinases, namely the epidermal growth factor receptor in vitro and the platelet-derived growth factor receptor in vivo. Low M(r) phosphotyrosine-protein phosphatase is constitutively tyrosine-phosphorylated in NIH/3T3 cells transformed by pp60v-src. The same tyrosine kinase, previously immunoprecipitated, phosphorylates this enzyme in vitro as well. Phosphorylation is enhanced using phosphatase inhibitors and phenylarsine oxide-inactivated phosphatase, consistently with the existence of an auto-dephosphorylation process. Intermolecular dephosphorylation is demonstrated adding the active enzyme in a solution containing the inactivated and previously phosphorylated one. This tyrosine phosphorylation correlates with an increase in catalytic activity. Our results provide evidence of a physiological mechanism of low M(r) phosphotyrosine-protein phosphatase activity regulation.

3T3 Cells↗

PubMed1996

Anosognosia for hemiplegia, neglect dyslexia, and drawing neglect: clinical findings and theoretical considerations.

In this paper different models of anosognosia are confronted and data concerning denial behaviors are presented that were collected on a selected population of right brain-damaged patients affected by motor and neglect disorders. Anosognosia for motor impairment and anosognosia for cognitive impairments were found to be dissociated, as well as anosognosia for the upper and lower limb motor impairments. These findings are then discussed in an attempt to choose the more suitable theoretical framework for interpreting the various disorders related to denial of illness.

Aged↗

PubMed1995

Differential modulation of expression of the two acylphosphatase isoenzymes by thyroid hormone.

The modulation of expression of the skeletal muscle and erythrocyte acylphosphatase isoenzymes by thyroid hormone has been investigated. Our results indicate a differential regulation of the two enzymic isoforms by tri-iodothyronine (T3) in K562 cells in culture: an increase in the specific mRNA during T3-stimulation is shown only for the skeletal muscle isoenzyme. A fast and transient T3 induction of the accumulation of the specific mRNA can be observed, reaching a maximum 8 h after hormone treatment and then rapidly decreasing almost to the steady-state level after 24 h. A nuclear run-on assay was performed to explore the mechanisms of this regulation. These studies indicate that T3 induction of skeletal muscle acylphosphatase mRNA is due, at least in part, to a fast and transient increase in the rate of gene transcription, within 4 h after hormone administration. A very rapid decrease is then observed within a further 2 h. T3-dependent accumulation of the mRNA for the skeletal muscle acylphosphatase requires ongoing protein synthesis, as confirmed by inhibition with cycloheximide or puromycin. These findings indicate that the transcriptional regulation of the gene may be indirect.

Acid Anhydride Hydrolases↗

PubMed1995

PDGF receptor as a specific in vivo target for low M(r) phosphotyrosine protein phosphatase.

Low M(r) phosphotyrosine protein phosphatase (LMW-PTP) is a 18 kDa cytosolic enzyme widely distributed in eukaryotic cells. LMW-PTP catalyses the hydrolysis of phosphotyrosine residues and overexpression of the enzyme in normal and transformed cells inhibits cell proliferation. Site directed mutagenesis, together with crystallographic studies, have contributed to clarify the catalytic mechanism, which involves the active site signature sequence C12XXXXXR18, a main feature of all PTPase family members. In order to identify the LMW-PTP substrate/s we have expressed in NIH-3T3 cells a catalytically inert Cys12 to Ser phosphatase mutant which has preserved its capacity for substrate binding. Overexpression of the mutant phosphatase leads to enhanced cell proliferation and serum induced mitogenesis, indicating that the mutation results in the production of a dominant negative protein. Analysis of mutant LMW-PTP expressing cells has enabled us to demonstrate an association between LMW-PTP and platelet derived growth factor receptor that appears to be highly specific. Our data suggest a catalytic action of LMW-PTP on the phosphorylated platelet derived growth factor receptor.

3T3 Cells↗

PubMed1995

Analogical representation and language structure.

Severe impairment of the analogue of mental representation is not compensated for by putative language-based cognitive processes in non-dysphasic brain-damaged patients. This undermines the hypothesis of an independent role for language in the generation of thought. Against this view it may be contended that there seems to be no obvious way in which analogical mental representation can decide between alternative syntactical structures available for the expression of thought. We performed a visual imagery experiment in which we asked 40 subjects to imagine visual scenes representing the meanings of simple utterances presented to them. The subjects then had to indicate the relative position, in each visual image, of two objects mentioned in each utterance. Series of utterances were presented differing syntactically (active or passive phrase) and semantically (specifying in different ways the spatial and temporal relations between the objects mentioned). The results of this mental imagery experiment indirectly support the hypothesis that syntactical structures can be represented in a nonlinguistic analogue medium.

Adult↗

PubMed1995

Unilateral neglect can be affected by stimuli in the neglected field.

Neglect patients' attention is usually pathologically captured by stimuli present on the side ipsilateral to the brain damage. In previous research it was shown that not only the mere presence but also the number of "relevant" stimuli on the right side influenced patient's performance. However, the influence of stimuli whose presence was completely irrelevant for the execution of the task was not previously studied. We asked neglect patients to bisect lines of 28 cm of length, which could be presented alone or with line-drawings of objects placed either only on the left, only on the right or bilaterally on the display. We found that the presence of irrelevant left-side stimuli improved the bisection performance in 3 out of 5 patients with respect to the baseline condition, in which, no stimuli were present on either side of the display. Right-side stimuli did not affect the performance, whereas bilateral stimuli tended to worsen the performance for those patients who presented the beneficial effect of left-side stimuli. These findings were discussed with reference to the hypotheses advanced to explain neglect.

Adult↗

PubMed1995

Awareness of and memory for arm weakness during intracarotid sodium amytal testing.

The traditional association between anosognosia for hemiplegia and the right hemisphere was investigated in 31 patients with unilateral temporal lobe pathology during intracarotid sodium amytal testing (ISA) before epilepsy surgery. Recall of arm weakness was examined by questioning at the end of the test, when memory for items presented during the hemiplegia was also examined. Significantly more patients were amnesic for left arm weakness than for right. Amnesia for right arm weakness (and speech arrest) was significantly associated with pathology in the temporal lobe on the non-injected side and with impaired recognition of the memory items. Amnesia for left arm weakness was independent of both. Examination of cases where injection was contralateral to a hemisphere without pathology, and which showed normal memory capacity under ISA conditions, revealed that 87% recalled right arm weakness, but only 22% recalled left arm weakness. Awareness of arm weakness during left hemiplegia was examined in nine patients. Five of them were not aware of the weakness. Three of the four others could not subsequently recall it. By inference from the generally unimpaired recall of right arm weakness, following left hemisphere inactivation by amytal, an intact right hemisphere is capable of both recognizing right arm weakness and mediating its subsequent recall. In contrast, the left hemisphere was aware of left arm weakness only in approximately 50% of cases and even when there had been awareness usually could not mediate its subsequent recall. The suggestion is made that the right hemisphere may have a specific mnestic function for arm weakness, and presumably for hemiplegia, additional to the gnostic function.

Adolescent↗

PubMed1995

The backflow from the pulmonary circulation for identification of the aortic origin of the bronchial arteries in experimental left single lung transplantation.

The ideal solution to the bronchial healing problems in lung transplant would be the reconstruction of the bronchial arteries at time of transplantation. The problems with this approach are essentially technical being difficult to identify and preserve the bronchial arteries in humans. The purpose of this paper is to report our experience with an experimental model in dog to easily identify and preserve bronchial circulation in single lung transplantation. The technique is based on the preservation during harvesting of the aortic origin of the first five couples of arterial orifices. Identification of the orifice(s) connected with the bronchial circulation is carried out by the backflow which takes place from the pulmonary circulation after organ reperfusion is resumed. The identified orifice(s) is then anastomosed to the descending recipient aorta, tangentially clamped.

Animals↗

PubMed1995

[Traumatic tearing of the mesentery: immediate or deferred emergency surgery].

We have considered a 1 year first-aid survey and focused a 6 checked mesentery vascular traumatic tearing cases. We have valued some hypotheses on pathogenic mechanism assumptions about these vascular injuries in abdomen trauma. Among these, we have focused our attention on the relationship between visceral stretching from alimentary bolus and abdominal vascular trauma. During diagnosis, we valued the importance of abdominal sounding, of echotomography and Computerized Tomography; the first one seems to be remarkable for reliability and quickness of accomplishment. In one case we have performed laparoscopic diagnostic-therapeutic approach. We suggested some standards for surgery choice related to injury amount. Monitoring is particularly important for those patients it can performed by invasive or image means seen that the unacknowledged endo-abdominal injury increases mortality by about 5-65%.

Adolescent↗

PubMed1995

[Results of 100 pulmonary and cardiopulmonary transplants in 95 patients at the Louis Pradel Hospital (Lyon) from 1988 to 1994].

From June 1989 to December 1994, 95 patients underwent 100 pulmonary and cardiopulmonary transplants. The patients were 58 men and 37 women with an average age of 39 +/- 15 years. In 15 of the cases, indication for a transplant was infectious pathology, in 35 of the cases; vascular pathology, in 23 of the cases; emphysema and in 22 of the cases the causes were various. 31 of the patients underwent a heart/lung transplant, 14 underwent a sequential two-lung transplant, 14 underwent a sequential two-lung transplant and 50 underwent a single lung transplant; 5 patient underwent a second transplant. The global survival percentage is 56,4 +/- 5,2 to one year, 48,5 +/- 5,4 to two years, 42,9 +/- 5,7 to three years. There are non significant statistical differences for the survival level according to the type of transplant. The best functional results were obtained from patients affected with emphysema. The survival data for patients affected with infectious pathology are not very encouraging.

Adolescent↗

PubMed1994

Inhibition of cellular response to platelet-derived growth factor by low M(r) phosphotyrosine protein phosphatase overexpression.

The role of low M(r) phosphotyrosine protein phosphatase (PTPase) in the control of cell proliferation was studied. A synthetic gene coding for PTPase was transfected and expressed in NIH/3T3 fibroblasts. The effects of the enzyme were particularly evident when cells were stimulated by platelet-derived growth factor (PDGF). The mitogenic response to PDGF was decreased and the inhibition reached 90%. This effect was more pronounced with respect to fetal calf serum stimulation. Hormone-dependent autophosphorylation of the PDGF receptor was significantly reduced. These results demonstrate that low M(r) PTPase, a cytosolic enzyme, not only affects cellular response to PDGF but also reduces the membrane receptor autophosphorylation.

3T3 Cells↗

PubMed1994

Schizophrenia and substance abuse: the interface.

1. Starting from the hypothesis that schizophrenia is not a defined disease entity but may be part of a variety of "anomalous need disorders", the goal of our study (a sample of 30 patients) was to establish whether schizophrenia and substance abuse are caused by completely different factors or, on the contrary, are generated by similar processes. 2. The prevailing tendency to substance abuse and of a depression phase, that may be hardly elaborated, in this sample of patients with positive symptoms led us to a common denominator of the two disorders: a lacking structure where the symptom would substitute the defective element.

Adult↗

PubMed1994

Nonconscious reading? Evidence from neglect dyslexia.

In this study we present evidence which supports the view that reading mechanisms, if implicit assessed, are available also in the presence of a severe deficit of spatial awareness. A Stroop-like task was performed by a right brain-damaged patient affected by severe extrapersonal neglect and neglect dyslexia. In reading words and color words, the patient showed the usual pattern of neglect errors; omission, substitution and addition errors. However, when asked to name the colors in which color words were written, naming time was found to be affected by the meaning of those words he was not able to read correctly. The pattern of results in MD and in a group of normal subjects, who performed a modified version of the Stroop test performed by MD, have been interpreted as evidence of MD's implicit reading of the left-hand letters of color words during the Stroop test. The theoretical implications of this finding are discussed. Moreover, the comparison between the performance of MD and the performance of another group of normal subjects suggested that implicit processing in MD was carried out at a lower level of efficiency than in normals.

Adult↗

PubMed1993

Negative growth control by a novel low M(r) phosphotyrosine protein phosphatase in normal and transformed cells.

Having determined the complete amino acid sequence of a cytosolic phosphatase purified from bovine liver, we studied the role of this enzyme (referred to as 'PTPase') in the control of cell proliferation. We used NIH/3T3 fibroblasts, both normal and transformed by the oncogenes v-erbB, v-src, and v-raf: a synthetic gene coding for PTPase was transfected into, and overexpressed in, normal and transformed NIH/3T3 cells with resulting inhibition of cell growth. Inhibition of proliferation correlated with the level of foreign PTPase; growth in soft agar was also inhibited in transformants overexpressing the enzyme. However, PTPase overexpression did not inhibit the rapid turnover of inositol lipids stimulated by platelet-derived growth factor. We conclude that this novel PTPase is active on cell type-specific signalling substrates that control normal and transformed fibroblast proliferation.

3T3 Cells↗

PubMed1993

High-frequency perfusion fluorometry (HFPF): preliminary results on a new technique for assessing bronchial mucosa blood perfusion.

A new method for estimating airway mucosa blood perfusion is proposed. It is based on the use of a high-sensitivity perfusion fluorometer, which allows us to detect the first intravascular passage of injected fluorochromes. Total measuring time can be sensibly reduced with respect to standard perfusion fluorometry, allowing us to make assessments during fiberoptic bronchoscopy. In vitro studies were performed to set up the optical arrangement of the instrument. The optimal measuring distance (2.2 mm) between the probe tip and the fluorescent mucosa was established using a fluorescent film surface to simulate fluorescent mucosa. The depth of tissue layers involved in the fluorescence emission was assessed by positioning tissue sections of different thickness between the probe tip and the fluorescent film. Tissue layers at depths not exceeding 1200 microns were found to contribute to the fluorescence signal recorded by the instrument. Mucosa blood perfusion was evaluated in rat trachea, as a model, under three different experimental conditions of vascularization: (a) basal condition (BC), (b) partial devascularization (PD), (c) full devascularization (FD). Sodium fluorescein (diffusible into the interstice) and fluorescein isothiocyanate-dextran (not diffusible into the interstice) were used as fluorescent tracers. Under the BC both substances allowed us to detect the first passage of fluorochrome through the mucosa capillary network with the same accuracy. In PD the first pass peak disappeared; total emitted fluorescence decreased as well. In FD a flat tracing was recorded. Consistent results were obtained with both substances.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Biocompatibility and biodegradation of different hyaluronan derivatives (Hyaff) implanted in rats.

Hyaluronan (HL), a naturally occurring glycosaminoglycan, has been chemically modified through the esterification of its carboxylic groups with different types of alcohol. The physico-chemical properties of these new biopolymers allow the preparation of many biomaterials which may be used in several medical applications. In the present study both the biocompatibility and biodegradation of some water-insoluble HL esters have been evaluated, either as raw material or as manufactured devices after subcutaneous and intraperitoneal implantation in male rats. The inflammatory response and the degree of resorption for each tested material are reported. The relationships between the degree of esterification and the type of alcohol used with the above parameters are also investigated.

Animals↗

PubMed1992

Differential role of four cysteines on the activity of a low M(r) phosphotyrosine protein phosphatase.

In this paper we describe the construction of five mutants of a bovine liver low M(r) phosphotyrosine protein phosphatase (PTPase) expressed as a fusion protein with the maltose binding protein in E. coli. Almost no changes in the kinetic parameters were observed in the fusion protein with respect to the native PTPase. Using oligonucleotide-directed mutagenesis Cys-17, Cys-62 and Cys-145 were converted to Ser while Cys-12 was converted to both Ser and Ala. The kinetic properties of the mutants, using p-nitrophenyl phosphate as substrate, were compared with those of the normal protein fused with the maltose binding protein of E. coli; both of the Cys-12 mutants showed a complete loss of enzymatic activity while the specific activity of the Cys-17 mutant was greatly decreased (200-fold). The Cys-62 mutant showed a 2.5-fold decrease in specific activity, while the Cys-145 mutant remained almost unchanged. These data confirm the involvement of Cys-12 and Cys-17 in the catalytic site and suggest that Cys-62 and Cys-145 mutations may destabilise the structure of the enzyme.

ATP-Binding Cassette Transporters↗